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Chemistry Retrieval Practice QuestionsTopic 0 – Chemistry FundamentalsSpec RefNo.QuestionAnswer?1Define atomThe smallest part of an element that can still be recognised as that element?2Define elementA substance made of only one type of atom?3Define compoundA substance made of two or more different atoms chemically bonded together?4Define moleculeA substance made of more than one atom chemically bonded together (can be atoms of the same type!)0.15What is the formula of the hydroxide ion?OH-0.16What is the formula of the sulphate ion?SO42-0.17What is the formula of the nitrate ion?NO3-0.18What is the formula of the group 1 metal ions?Li+, Na+, K+0.19What is the formula of the group 2 metal ions?Be2+, Mg2+, Ca2+0.110What is the formula of the oxide ion?O2-0.111What is the formula of the ammonium ion?NH4+0.512What does this hazard symbol mean? Corrosive0.513What does this hazard symbol mean? Environmental hazard0.514What does this hazard symbol mean? Toxic0.515What does this hazard symbol mean? Irritant 0.316What does (aq) stand for?Aqueous: when something is dissolved in water. E.g. NaCl(aq) is salt water0.317What does (s) stand for?solid0.318What does (l) stand for?liquid0.319What does (g) stand for?Gas ?20What safety measures should you use if a practical produces a toxic gas?Use a fume cupboardTopic 1 – Atomic Structure1.221State the three subatomic particlesProtons, neutrons, electrons1.322State the masses of the subatomic particlesProtons: 1, neutrons: 1, electrons: 01.323State the relative charges of the subatomic particlesProtons: +1, neutrons: 0, electrons: -11.324How are the subatomic particles arranged in an atom? Protons and neutrons in the nucleus, electrons orbiting in shells1.725What is the mass number of an atom?The number of protons + the number of neutrons in an atom1.126How do you calculate the number of neutrons in an atom?Mass number - atomic number1.327What is the mass and charge of a neutron? Mass = 1 Charge =01.428Why do atoms have no overall charge?Because they have the same number of electrons as protons so the charges cancels each other out.1.529How does the size of the nucleus compare to the size of the atom?Nucleus is very small1.1230How can you calculate relative atomic mass given isotopes masses and abundances?(mass 1 x abundance) + (mass2 x abundance) / 1001.931What are isotopes?Atoms of the same element with different mass numbers1.932What are the similarities and differences between isotopes?Same number of electrons and protons but a different number of neutrons.1.10.33Sodium has a mass number of 23, and an atomic number of 11. How many electrons, protons and neutrons?11 protons, 11 electrons, 12 neutrons1.10.34Aluminium has a mass number of 27, and an atomic number of 13. How many electrons, protons and neutrons?13 protons, 13 electrons, 14 neutrons?35What makes an atom a particular type of atom?Each type of atom has a number of protons, a different number of protons would make something a different type of atom.1.1136What are some of the values for relative atomic mass not whole numbers?They are the average mass of an atom of that isotope, there are several kinds each present in a different amount. So the average is not a whole number.?37How do you work out the mass number of an element?no. protons + no. Neutrons?38What do you do when asked to compare 2 atoms given atomic number and mass number?State how many electrons, protons and neutrons they both have.?39Neon has a mass number of 20, and an atomic number of 10. How many electrons, protons and neutrons?10 protons, 10 electrons, 10 neutrons?40Nitrogen has a mass number of 14, and an atomic number of 7. How many electrons, protons and neutrons?7 protons, 7 electrons, 7 neutronsTopic 1 – Periodic Table1.1641What is the atomic number of an atom?The number of protons in an atom1.1642What can the period tell you about the electrons in an atom?How many shells an atom has. E.g. carbon is in the second period so has two shells1.1343Why did Mendeleev put some elements in groups?Because they had similar chemical properties (e.g. they reacted violently with water)1.1544What did Mendeleev put the elements in order of?Increasing atomic mass1.1545How is the modern periodic table organised?In order of increasing atomic number1.1446Why did Mendeleev leave gaps in his periodic table?For elements that had not been discovered yet?47What are groups in the periodic table?The columns, numbered 1, 2, 3, 4, 5, 6, 7, 01.1648What can the group tell you about the electrons in an atom?How many electrons in the outer shell. E.g. carbon is in group 4 so has 4 electrons in the outer shell1.1949How are the electrons arranged in atoms?Orbiting the nucleus in shells1.1950Where are the metals found on the periodic table?on the left hand side1.1951How many electrons does calcium have?20 (same as atomic number!)1.1952How many electrons does silicon have?14 (same as atomic number!)1.1953How are the electrons in sulphur arranged?2.8.6 (18 electrons total)1.1954How are the electrons in magnesium arranged?2.8.2 (12 electrons total)1.1955How many electrons are in the outer shell of boron?3 (it is in group 3!)1.1956How many electrons are in the outer shell of phosphorous?5 (it is in group 5!)1.1957How many electrons are in the outer shell of sodium?1 (it is in group 1!)1.20.58An element has three shells and three electrons in the outer shell. What element is it?Aluminium (group 3, period 31.1959How many electrons are in the outer shell of Gallium?3 (it is in group 3!)1.1960How many electrons can go in the first shell? How many in the second shell?2 = 1st shell, 9 = second shellTopic 1 – Bonding – Part 11.2161Why do atoms transfer electrons in ionic bonding?So that they can have full outer shells1.2462Explain in terms of electrons what occurs when lithium bonds with fluorine One electron transferred from lithium to fluorine1.2463Explain in terms of electrons what occurs when magnesium bonds with oxygenTwo electrons transferred from magnesium to oxygen1.2464Explain in terms of electrons what occurs when beryllium bonds with oxygen (3 marks)Two electrons transferred from beryllium to oxygen1.2465Explain in terms of electrons what occurs when magnesium bonds with chlorineOne electron transferred from magnesium to two different chlorine atoms1.2466Explain in terms of electrons what occurs when sodium bonds with oxygen Two electrons transferred to an oxygen atom from two different sodium atoms1.2467Why do sodium ions and chlorine ions form an ionic bond? There is an electrostatic force of attraction between oppositely charged ions1.2468Why don't sulphur ions and oxygen ions form ionic bonds with each other?Both have negative charges so would repel1.2269What is the name for a substance made of billions of oppositely charged ions joined together?Giant ionic lattice1.2770Define giant ionic latticeA huge 3D network of ions1.3371State the melting points of ionic substancesHigh1.3372Explain why ionic substances have high melting points.Strong bonds between oppositely charged ions are hard to break1.3373Will NaCl(s) conduct electricity?No1.3374Will NaCl (aq) conduct electricity?Yes (aq stands for aqueous which means it is dissolved in water)1.3375Will NaCl (l) conduct electricity?Yes1.3376What does molten mean?Melted1.3377Explain why ionic compounds do not conduct electricity when solid Because the ions are not free to move1.3378Explain why ionic compounds conduct electricity in solution Because the ions are free to move1.3379Explain why ionic compounds conduct electricity when molten Because the ions are free to move1.2980Explain why chlorine and fluorine form covalent bondsThey are both non-metalsTopic 1 – Bonding – Part 21.2881Complete the sentence: In covalent bonds, electrons are _______________________Shared1.3482In ionic bonds, electrons are ___________________Transferred1.3583What is the name given to the structure of diamond, graphite and silicon dioxide?Giant covalent1.3684How many bonds does each carbon have in diamond?41.3785Explain why diamond has a high melting point Giant structure, Strong covalent bonds between the atoms, requires a lot of energy to break1.3786Explain why most giant covalent substances do not conduct electricity (3 marks)There are no electrons/ions/charged particles that are free to move1.3787Explain why graphite conducts electricity Has delocalised electrons between the layers that can move through the graphite1.3788Explain why graphite can act as a lubricantWeak forces between layers which are free to slide over each other1.3889What is graphene?One layer of graphite1.3890What is a fullerene?Substance made of carbon atoms arranged in a cage1.3291What type of substance are methane and water?Simple molecular (or simple molecules)1.2992What is a molecule?A group of atoms chemically bonded together1.3193Describe the structure of simple covalent moleculesStrong covalent bonds between atoms, weak forces holding the molecules together1.3494What are intermolecular forces?Weak forces between molecules which hold them together1.3495Explain why methane has a low melting pointIt is a simple molecular substance with weak forces between the molecules (which are easy to break)1.3996What is a polymer?Millions of small molecules joined together in a chain to form a large molecule1.40.97Describe the main features of metals in terms of their structurePositive metal ions arranged in layers with delocalised electrons1.4298Explain why metals can conduct electricity Delocalised electrons are free to carry charge1.4299Explain why pure metals are soft Layers of metal ions are free to slide over each other1.21100Explain in terms of electrons what occurs when lithium bonds with chlorine One electron transferred from lithium to chlorineTopic 1 – Bonding – Part 31.21101What charge will an ion of lithium take?1+ (one electron in the outer shell, needs to lose it)1.21102What charge will an ion of beryllium take?2+ (two electrons in the outer shell, needs to lose them both)1.21103What charge will an ion of barium take?2+ (group 2 so two electrons in the outer shell, needs to lose them both)1.21104What charge will an ion of fluorine take?1- (7 electrons in the outer shell, needs to gain one)1.21105If something has gained electrons, what charge will it have?Negative1.21106If something has lost electrons, what charge will it have?Positive (because they have lost a negative!)1.21107What charge will an ion of oxygen take?2- (6 electrons in outer shell so needs to gain two)1.24108What is an ion?an atom which has lost or gained an electron1.23109How many electrons, protons and neutrons in a sodium ion Na+ ?11 protons, 12 neutrons, 10 electrons1.41110What are the limitations of dot and cross diagrams.It does not show the shape of the molecule or the size of the atoms.1.25111If a compound name ends in -ate what does this show?It is a molecule made of the other elements in the name and oxygen.1.41112What are the limitations of a ball and stick modelIt does not show the electrons involved in the bonds. It does not show the 3d shape1.25113What elements are in sodium sulfate?Sodium, sulfur and oxygen1.25114If a compound name ends in -ide what does this show?It is a molecule made of 2 elements only.1.23115How many electrons, protons and neutrons in an oxygen ion O2- ?8 protons, 8 neutrons, 10 electrons1.23116How many electrons, protons and neutrons in a chloride ion Cl- ?17 protons, 18 neutrons, 18 electrons1.23117How many electrons, protons and neutrons in a magnesium ion Mg2+ ?12 protons, 12 neutrons, 10 electrons1.25118What elements are in potassium hydroxide?potassium, oxygen and hydrogen1.25119What elements are in sulfuric acid?hydrogen, sulfur and oxygen1.25120What elements are in iron carbonateiron, carbon and oxygenTopic 2 – States of Matter2.2121Define mixtureA substance made of more than one thing not chemically bonded together?122What are the 3 states of matter?Solid, liquid and gas2.2123What is the change from a solid to a liquid called?Solid ? liquid – melting2.4124If the temperature is above the melting point of a substance but below the boiling point of a substance what state will it be in?Liquid2.4125If the temperature is below the melting point of a substance and below the boiling point of a substance what state will it be in?Solid 2.4126If the temperature is above the melting point of a substance and above the boiling point of a substance what state will it be in?Gas 2.2127What is the change from a liquid to a gas called?Liquid ? gas – evaporation2.2128What is the change from a gas to a liquid called?gas ? liquid – condensation2.2129What is the change from a liquid to a solid called?liquid ? solid – freezing2.1130Describe the arrangement of the particles in a solidparticles closely packed, in a regular arrangement2.1131Describe the arrangement of the particles in a liquidparticles closely packed, but in a random arrangement2.1132Describe the arrangement of the particles in a gasparticles spaced far apart in a random arrangement2.4133A substance has a melting point of 25 oC and a boiling point of 235 oC. What state is it at 5oC?Solid2.4134A substance has a melting point of -125 oC and a boiling point of -35 oC. What state is it at 15oC?Gas2.4135A substance has a melting point of -25 oC and a boiling point of 35 oC. What state is it at 25oC?liquid2.32136Describe how the particles change in arrangement when a solid turns into a liquidForces between particles weaken and they move more freely. The particles are not arranged in order2.32137Describe how the particles change in arrangement when a liquid turns into a solidForces between particles weaken and they move freely. They are spaced far apart2.32138Describe how the particles change in arrangement when a gas turns into a liquidForces strengthen, particles move closer together2.32139Describe how the particles change in arrangement when a liquid turns into a gasForces strengthen, particles move close together in ordered rows2140Describe the melting and boiling points of pure substancesOne very specific temperatureTopic 2 – Separating Techniques2.7c141What is chromatography?A process to separate the constituents of a mixture2.9142In paper chromatography, what is the stationary phase and what is the mobile phasePaper is stationary, solvent (usually water or ethanol) is mobile2.1143How can chromatography show the difference between pure and impure substances?Pure ones will not separate into a number of spots2.10.144How is the Rf value calculated?distance moved by spot/distance moved by solvent2.10.145What does a substance's Rf value depend on?How soluble it is in the solvent2.9146In chromatography, why must the substances be placed on a pencil line?Pencil will not dissolve in the solvent2.9147In chromatography why must the solvent height be lower than the pencil line?So that the substances do not dissolve into the solvent off the paper2.6148How is the melting point of a pure substance different from that of an impure substance?Pure substance has one specific melting point. Impure substance has a melting range.2.7a149What is simple distillation used to separate?A liquid from a solid2.7b150What is fractional distillation used to separate?Two liquids with different boiling points.2.7c151What is filtration used to separate?An insoluble solid from a liquid2.7d152What is crystallisation?Forming crystals of a soluble solid from a solution.2.12153What is potable water?Drinking water2.12154How can sea water be made potable?By distillation2.12155What are the stages used to make water potable.Sedimentation, filtration and chlorination2.5156What is a pure substance?A substance made of one type of atom or molecule only.2.8157How would you separate water from salt water?Simple distillation2.8158How would you separate salt from salt water?Crystallisation2.12159Why must analysis be done with pure water?Because dissolved salts in non pure water would give false positive results.2.5160How is the melting point of a mixture different from a pure substance?A pure substance has a single melting temperature, a mixture has a range of melting ic 3 – Acids – Part 13.19161What does soluble mean? What does insoluble mean?Dissolves in water. Does not dissolve in water3.1162Define acid in terms of pHA substance with a pH of less than 73.1163Define acids in terms of ionsA substance which releases H? ions in solution?164State the three common acids and give their formulaeHydrochloric acid, HCl(aq), Sulphuric acid, H?SO?(aq), Nitric acid, HNO??165Which ions do the common acids form in solution?HCl forms H? and Cl?, H?SO? forms 2H? and SO???, HNO? forms H? and NO??3.2166What is a neutral solution?A solution with a pH of 7. Water is an example.3.3167How do you measure pH?With an indicator or pH probe.3.10.168What is a base?A metal oxide, hydroxide or carbonate that will react with an acid. E.g. copper oxide3.10.169What is an alkali?A soluble base. E.g. sodium hydroxide3.1170Which ions are always present in a solution of an alkali?OH?3.9171What is a salt?A compound formed when some or all of the hydrogen from an acid is replaced by a metal. E.g. CuSO?, copper sulphate, where copper has replaced H from H?SO??172What type of salts are formed by the three main acids?Hydrochloric acid produces chlorides, sulphuric acid = sulphates, nitric acid = nitrates3.14173What is a neutralisation reaction? Write an ionic equation for neutralisation.A reaction involving an acid that results in a neutral solution. H? + OH? → H?O3.14174Which ions always react together in a neutralization reactions between acids and alkalis?H? and OH?3.11a175metal + acid →→ salt + hydrogen gas3.11c176metal hydroxide + acid →→ salt + water3.11b177metal oxide + acid →→ salt + water3.11d178metal carbonate + acid →→ salt + water + carbon dioxide3.15179How do you make a soluble salt from an acid?React the acid with a base. E.g. to make copper sulphate react copper oxide with sulphuric acid3.21180If a salt is in solution, how do you extract it as a solid?Allow the water to evaporate off and it will leave the salt behind as a ic 3 – Acids – Part 23.8181What is a strong acid? An acid which completely splits up into its ions in water. E.g. when HCl is in water all the HCl molecules split up into H? and Cl?. 3.8182 What is a weak acid?An acid which will have some molecules which do not split up into their ions. E.g. in ethanoic acid only some of the molecules will have split up into the ethanoate ion and H? ions.3.4183What is the relationship between an acid of pH2 and an acid of pH 3?pH 2 is 10 times more hydrogen ions than pH 33.7184What is a concentrated acid?An acid where there are lots of acid particles in the water.3.7185What is a dilute acid?An acid where there are fewer acid particles in the water.3186How is pH measured?pH is related to the concentration of H? in a solution.3.12187How can hydrogen be tested for?Makes a squeaky pop when a splint is placed in it3.12188How can carbon dioxide be tested for?Bubble through limewater, turns it milky (cloudy)3.3189What colour is litmus in acid and alkali?Acid – red, alkali – blue3.3190What colour is methyl orange in acid and alkali?Acid – red, alkali – yellow3.3191What colour is phenol phthalein in acid and alkali?Acid – colourless, alkali – pink3.17192How do you prepare a sample of a soluble salt from a base and an acid?Neutralisation, filtration, crystallisation3.16193How do you prepare a sample of a soluble salt from an acid and an alkali?Titration, repeat titration without indicator, crystallisation3.21194How do you prepare a sample of an insoluble salt from two solutionsCombine, filtration.3.19195Soluble or insoluble? nitratesSoluble3.19196Soluble or insoluble? Sodium saltsSoluble3.19197Soluble or insoluble? Chloride saltsSoluble, except silver and lead compounds3.19198Soluble or insoluble? sulphatesSoluble, except lead, barium and calcium compounds3.19199Soluble or insoluble? carbonatesInsoluble, except sodium, potassium and ammonium3.19200Soluble or insoluble? hydroxidesInsoluble, except sodium, potassium and ammonium3.22201Magnesium carbonate is insoluble. What do you need to do before it will conduct electricity?Melt itTopic 3 – Electrolysis – Part 13.22202Sodium fluoride is soluble. Explain what the easiest way for it to conduct electricity is Dissolve it in water because this does not require high temperatures?203Which ions are in NaClNa? and Cl??204Which ions are in CuCl?Cu?? and two Cl??205Which ions are in Na?SO?2 ions of Na? and one SO???3.29206Is this process oxidation or reduction? Al → Al?? + 3e?Oxidation3.29207Is this process oxidation or reduction? Na? + e? → NaReduction3.29208Is this process oxidation or reduction? F? + 2e? → 2F?Reduction3.29209Is this process oxidation or reduction? Fe?? → Fe?? + e?Oxidation3.29210In this reaction, what has been oxidised and what has been reduced? Mg?? + 2Na → 2Na? + MgNa has been oxidised, Mg?? has been reduced3.29211In this reaction, what has been oxidised and what has been reduced? 2Al + 3Ca?? → 2Al?? + 3CaAl has been oxidised, Ca?? has been reduced3.29212In this reaction, what has been oxidised and what has been reduced? K + Na? → K? + NaK has been oxidized, Na? has been reduced3.23213What is electrolysis?Using a dc electric current to decompose (break down) a substance 3.23214What is an electrolyte?An ionic compound in the molten state or dissolved in water3.22215What happens to an ionic substance when it is melted or dissolved in water?The ions become free to move around3.24216What is the name for the positive electrode?The anode3.24217What is the name for the negative electrode?The cathode3.24218Do positive ions move to the anode or the cathode?Cathode3.24219Do negative ions move to the anode or the cathode?Anode3.24220Where does reduction occur?CathodeTopic 3 – Electrolysis Part 23.24221Where does oxidation occur?Anode3.24222At which electrode would Zn?+(aq) turn into Zn(s)?Cathode (needs to gain electrons)3.24223At which electrode would Cl?(aq) turn into Cl?(g)?Anode (needs to lose electrons)3.27224Balance the equation: Al?? + e? → AlAl?? + 3e? → Al3.27225Balance the equation: Cl? → Cl? + e?2Cl? → Cl? + 2e?3.27226Balance the equation: O?? → O? + e?2O?? → O? + 4e?3.26227What will be the products for the electrolysis of molten iron bromide?Iron and bromine3.26228What will be the products for the electrolysis of molten zinc oxide?Zinc and oxygen3.28229Define oxidation in terms of electronsOxidation is the loss of electrons4230Define reduction in terms of electronsReduction is the gain of electrons3.25231What will be the products for the electrolysis of sodium sulfate solution?Hydrogen gas and Oxygen gas3.25232What will be the products for the electrolysis of acidified water?Hydrogen gas and Oxygen gas3.31233What happens to the change in mass of the electrodes if you increase the current?As current increases so does the change in mass.3.31234When copper sulphate solution is electrolysed using copper electrodes. What happens to the mass of the electrodes?The cathode mass increases. The anode mass decreases.3.31235Why use propanone to dry the electrodes when reweighing them after the electrolysis.It evaporates drying the electrodes, no need to physically dry them.3.25236What will be the products for the electrolysis of copper chloride solution?Copper and chlorine3.25237What will be the products for the electrolysis of molten lead bromide?lead and bromine3.25238In the electrolysis of sodium chloride solution, what are the products?Chlorine gas and hydrogen gas3.25239Why is sodium not produced in the electrolysis of sodium chloride solution?It is more reactive than hydrogen so hydrogen is produced instead.3.25240What is produced at the anode in electrolysis of solutions?Either a halogen or oxygen (when there is no halogen present)Topic 4 – Metals4.2241For the extraction of which metals is electrolysis needed?Ones more reactive than carbon, e.g. aluminium4.7b242What are the two main disadvantages of using electrolysis to extract metals?Requires a large amount of energy to melt the compounds and to produce the necessary electricity4.7b243Why is aluminium oxide mixed with cryolite when extracting aluminium?To lower the melting point4.7b244What is produced at the anode and cathode in the electrolysis of aluminium oxide?Aluminium at the cathode and oxygen at the anode4.7b245Why does the anode need to be replaced in the electrolysis of aluminium oxide?The oxygen reacts with the carbon electrode to produce carbon dioxide.4.3246What is the reactivity series?A list of elements ordered by their reactivity. (K, Na, Ca, Mg, Al, (C), Zn, Fe, (H), Cu, Ag, Au)4.1247How can metals be placed in order of their reactivity?Add the metals to water or acid and see which ones react the most (by how much fizzing there is)4.5248What is the name for a reaction where oxygen is removed from a compound?Reduction4.7a249Explain why zinc can be extracted from zinc oxide with carbon but magnesium cannot be extracted from magnesium oxide with carbonMagnesium is more reactive than carbon (1), Zinc is less reactive than carbon (1), Carbon can therefore remove oxygen from zinc oxide but not magnesium oxide (1)4.4a250Explain why gold and silver can be found naturally in the Earth's crustIt is very unreactive4.7b251What process is used to extract metals more reactive than carbon? Why?Electrolysis. It is a stronger form of reduction.4.4a252Define an oreA material containing enough metal in it for it to be economically worthwhile to extract the metal.4.2253Define a displacement reactionA reaction in which a more reactive element takes the place of a less reactive element in one of its compounds or in solution4.2254Which of the substances below has been oxidized and which has been reduced? Al?? + Fe → Fe?? + AlAluminium has been reduced and iron has been oxidised4.2255Show two half equations for the reaction below: Al?? + Fe → Fe?? + AlAl?? + 3e? → Al, Fe → Fe?? + 3e-4.8256What is phytoextractionGrowing plants on areas of low grade ore, to concentrate the metal in the plant then extracting the metal from the plant.4.8257Why use phytoextractionAllows us to extract ores from sites where it would not otherwise be cost effective.4.11258What are the stages of a life cycle assessment?Effect on the environment of; obtaining raw materials, manufacturing the product, using the product and disposing of the product.4.2259How is copper extracted from its ore?Heating with carbon.4.6260In this displacement reaction. What is oxidised and what is reduced? CuSO4 + Mg → MgSO4 + CuCopper gains electrons and is reduced. Magnesium loses electrons and is ic 4 – Equilibrium4.13261What is a reversible reaction?A reaction which can go from reactants to products but also from products to reactants4.13262What chemical symbol represents a reversible reaction???263If a reaction is exothermic in the forward direction what will it be in the reverse direction?Endothermic?264Two reactants require 30kJ to turn into products. What energy transfer is involved when the products turn into reactants?30kJ is released4.14265What is equilibrium?The point in a reversible reaction when the forward and reverse reactions are occurring at the same rate4.14266How is the amount of reactant changing at equilibrium?It is not changing4.14267How is the amount of product changing at equilibrium?It is not changing4.17a268A reaction is exothermic in the forward direction. What will occur if the temperature is increased?The backward reaction will increase as it is endothermic and will reduce the temperature4.17a269A reaction is endothermic in the forward direction. What will occur if the temperature is increased?The forward reaction will increase as it is endothermic and will reduce the temperature4.17c270A reaction is at equilibrium when some product is removed. What will occur?The forward reaction will increase as that will increase the amount of product4.17c271A reaction is at equilibrium when the concentration of a reactant is increased. What will occur?It will move in the forward reaction to reduce the amount of the reactant.4.17b272The reaction below is at equilibrium. What will occur when the pressure is increased?2H?(g) + O?(g) ? 2H?O(g)The forward reaction will increase as there are fewer molecules on the right. This will reduce the total number of molecules and therefore the pressure.4.15273What is the Haber process reaction3H2(g) + N2 (g) ? 2NH3(g)4.16274What temperature is used for the Haber process?450 oC4.15275Where does the nitrogen for the Haber Process come from?Nitrogen from the atmosphere4.15276Where does the hydrogen for the Haber Process come from?Hydrogen from natural gas?277Why are the products of the reaction cooled?To turn the ammonia into a liquid and remove it, so driving the equilibrium in the forward reaction some more.4.14278What is a dynamic equilibrium?A reversible reaction where the forward reaction and the backward reaction happen at the same rate4.16279What catalyst is used for the Haber process?Iron catalyst4.16280What pressure is used for the Haber process?200 atmospheresTopic 6 – Periodic Table6.1281In terms of electrons, what do group 1 elements have in common?1 electron in the outer shell6.1282In terms of electrons, what do group 7 elements have in common?7 electrons in the outer shell6.1283In terms of electrons, what do group 0 elements have in common?Full outer shell6.4284What is more reactive, lithium or sodium?Sodium6.11285What is more reactive, chlorine or bromine?Chlorine?286Define inertUn-reactive6.14287Explain why the noble gases are inertThey have full outer shells, so do not need to gain or lose electrons6.2288State the trend in the melting points of the alkali metalsGets lower down the group6.6289What state are fluorine, chlorine, bromine and iodine at room temperature?Gas, gas, liquid, solid6.3290Balance the equation: Li + H?O → LiOH + H?2Li + 2H? → 2LiOH + H?6.7291State the trend in melting and boiling points for the halogens as you go down the group. Predict what state astatine will be.As you go down the group melting point increases. F2 and Cl2 are gases, Br2 is a liquid, I2 is a solid. At2 will be a solid6.8292How can chlorine be tested for?Bleaches damp litmus paper white6.3293Explain why the group 1 elements are called alkali metalsThey are metals that form alkalis when they react with water 6.11294What is a displacement reaction?A reaction in which a more reactive element takes the place of a less reactive element in a compound6.11295Explain why the following reaction does not proceed: KBr + I?Iodine is less reactive than bromine so cannot displace it6.11296Balance the below equation and explain why it is a displacement reaction: KBr + Cl? → KCl + Br?2KBr + Cl? → 2KCl + Br? , chlorine has displaced bromine as it is more reactive6.13297Explain why fluorine is more reactive than chlorineFewer shells/electrons, less shielding (or stronger attraction from nucleus), easier to gain electrons6.5298Explain why potassium is more reactive than lithium (3 marks)More shells/electrons, less shielding (or weaker attraction from nucleus), easier to lose electrons6.9299How do halogens react with magnesium?Mg (s) + Cl2 → MgCl2 (s)6.1300What happens with halogens react with hydrogen? What is the pH when the product dissolves in water?H2 (g) + Cl2 (g) → 2HCl (g) - pH will be low as forms an acidTopic 7 – Rates of Reaction7.2301What is the rate of a chemical reaction in terms of reactants?How quickly the reactants in a reaction are used up7.2302What is the rate of a chemical reaction in terms of products?How quickly the products in a reaction are formed7.2303What is the formula for a mean rate of reaction in terms of reactants?quantity of reactant used/time taken7.2304What is the formula for a mean rate of reaction in terms of products?quantity of reactant product formed/time taken7.2305How can you measure the quantity of a reactant or product?In grams or in cm?7.2306What are the two possible units for rate of reaction?g/s or cm?/s (where s is seconds)7.5307How could you measure the rate of a reaction from a graph?Draw a tangent to the curve and calculate the gradient.7.3308What is "collision theory"?The theory that chemical reactions only occur when particles collide with sufficient energy7.4309What factors can affect the rate of a reaction?Temperature, surface area of a solid, concentration or reactants in solution, pressure of gases7.4310State the effect of increasing the surface area on the rate of a reactionIncreases the rate7.4311Explain why increasing the surface area increases the rate of a reactionMore particles are available to collide, there are therefore more frequent collisions between reactants.7.4312State the effect of increasing the concentration on the rate of reactionIncreases7.4313Explain why increasing the concentration increases the rate of reactionMore concentrated means more particles in solution, therefore more frequent collisions between reactants.7.4314State the effect on increasing the pressure of a gas on the rate of reactionIncreases7.4315Explain why increasing the pressure of a gas increases the rate of a reactionLess space for the particles to move around in, therefore more frequent collisions7.4316State the effect of increasing the temperature on the rate of reactionIncreases7.4317What is the activation energy?The amount of energy a particle needs before it will be able to react when it collides with another particle7.4318Explain why increasing the temperature increases the rate of reactionIncreases the speed at which particles move therefore more frequent collisions. Increases the number of particles which have the activation energy therefore more collisions result in a reaction.7.6319What is a catalyst?Something which changes the rate of a reaction but is not used up in that reaction7.6320How do catalysts speed up reactions?They provide another route for the reaction to take place which has a lower activation ic 7 – Energy in Reactions7.8321What supplies the enzyme for producing alcoholic drinksYeast?322How does the law of conservation of energy apply to chemistry?In all chemical reactions, energy is either transferred to the surroundings or from the surroundings.7.10.323What is an exothermic reaction?A reaction where energy is transferred to the surroundings.7.9324Give two examples of exothermic bustion, respiration7.10.325What happens to the temperature of the surroundings during an exothermic reaction?They increase. The thermometer is included in "the surroundings" so shows the temperature increasing.7.11326What is an endothermic reaction?A reaction where energy is transferred from the surroundings.7.9327Give two examples of endothermic reactions.Thermal decomposition reactions, citric acid and sodium hydrogencarbonate.7.11328What happens to the temperature of the surroundings during an endothermic reaction?They decrease. The thermometer is included in "the surroundings" so shows the temperature decreasing.?329State two uses of exothermic reactionsSelf-heating cans, hand warmers?330State two uses of endothermic reactionsSome cooling sports injury packs?331What are reactants?The substances involved in a chemical reaction?332What are products?The substances formed when reactants have a chemical reaction7.16333What is a reaction profile?A diagram which shows whether the reactants have more or less energy than the products.7.10.334If the reactants have more energy than the products, what kind of a reaction must have taken place?An exothermic one. The missing energy has been transferred to the surroundings.7.11335If the reactants have less energy than the products, what kind of a reaction must have taken place?An endothermic one. The extra energy has been taken in by the surroundings.7.12336Is breaking bonds endothermic or exothermic?Endothermic. Chemical bonds are strong so require energy to break (like when you have to put energy in to separate magnets from each other)7.12337Is making bonds endothermic or exothermic?Exothermic. Energy is released when chemical bonds are formed (like how two magnets move together when close and generate kinetic energy)7.14338How do we work out the overall energy change of a reaction?Work out the difference between the energy needed to break all the bonds in the reactants and the energy released to form all the bonds in the products.7.13a339If more heat energy is released forming bonds than is required for breaking bonds in a reaction what kind of reaction is it?exothermic7.13b340If less heat energy is released forming bonds than is required for breaking bonds in a reaction what kind of reaction is it?endothermicTopic 8 – Fuels – Part 18.2a341What is crude oil?A mixture of hydrocarbons?342What is crude oil formed from?The remains of ancient biomass (mostly plankton) that was buried in mud8.2d343What is a finite resource? Why is crude oil a finite resource?One that will run out. Because it takes longer to form than the rate at which we are using it up8.1344What is a hydrocarbon?A compound made of atoms of carbon and hydrogen only8.6345What is an alkane?A hydrocarbon with only single bonds8.6346Name the first four alkanesMethane, ethane, propane, butane8.6347What is the general formula for alkanes?CnH2n+2 (the n and 2n are small)8.6348How does boiling point change with the length of an alkane?The longer the alkane, the higher its boiling point8.5349How does viscosity change with the length of an alkane?The longer the alkane, the more viscous (the thicker) it is8.5350How does flammability change with the length of an alkane?The longer the alkane, the less flammable it is8.3351What is fractional distillation?A process used to separate mixtures of substances with different boiling points8.3352What are the steps involved in fractional distillation?Crude oil is vaporised, different molecules rise up the fractionating column and cool down. Condense at different points on the column.8.3353Why is fractional distillation important?Because the different fractions have different uses8.4354What is a fuel?A substance which when reacted with oxygen releases energy8.4355Name five fuels we obtain from crude oilPetrol, diesel oil, kerosene, fuel oil and liquefied petroleum gases8.4356What other uses are there for products of fractional distillation?Solvents, lubricants, polymers and detergents8.7357What is combustion?The reaction of a fuel with oxygen8.7358What are the products of complete combustion?Carbon dioxide and water8.8359When does incomplete combustion occur?When there is not enough oxygen present8.8360What is formed in incomplete combustionCarbon monoxideTopic 8 – Fuels – Part 28.9361Why is carbon monoxide dangerousIt is toxic, taken up by red blood cells in preference to oxygen.8.16362What is cracking?The process of breaking down a long hydrocarbon into smaller hydrocarbons8.16363What are the products of cracking?Short alkanes and alkenes8.17364Why is cracking important?Because smaller hydrocarbons are more useful than longer ones8.6365What are alkenesA hydrocarbon with a double bond8.6366What are alkenes used for?As a starting material to make more useful chemicals8.6a367What is the general formula for alkenes?CnH2n9.12368What are the first four alkenes?Ethene, propene, butene, pentene8.6369What do members of a homologous series have in common?Same general formula, differ by CH2 for neighbouring compounds in the series, boiling points increase with chain length, have similar chemical properties and reactions. 8.11370How is sulphur dioxide produced?Sulphur impurities in fuels form it when the fuel is burnt8.12371What happens when the sulphur dioxide dissolves in rain water?Acid rain is formed8.13372How are oxides of nitrogen formed?When the nitrogen and oxygen in the air react together at the high temperatures created in combustion engines8.14373State three advantages of hydrogen fuel cells over petrolDo not need to be recharged, no pollutants are produced only H2O, water is a renewable resource8.14374State three disadvantages of hydrogen fuel cells over petrolHydrogen is highly flammable, hydrogen is sometimes produced through non-renewable means, hydrogen is difficult to store and transport8.2d375What does finite mean?It wil run out.8.5c376How does ease of ignition change with the length of an alkane?The longer the alkane, the harder it is to ignite.8.5b377How are members of a homologous series different from each other?Their chain length differs by a number of CH28.15378Where do petrol, kerosene and diesel oil come from?They are obtained by fractional distillation of crude oil8.15379Where does methane come from?It is found in natural gas?8.15380Are petrol, kerosene, diesel and methane renewable or non renewable?non-renewableTopic 8 – Atmosphere8.23381How can oxygen be tested for?Relights a glowing splint8.19382What gases made up the Earths initial atmosphereLarge amount of carbon dioxide, water vapour, small amounts of other gases8.20.383What happened to the water vapour as the earth cooled?Water vapour condensed forming oceans8.21384What affect did the formation of the oceans have on the amount of carbon dioxide in the atmosphere?Carbon dioxide dissolves in water so some dissolved and the amount in the atmosphere decreased8.22385How did the growth of primitive plant affect the atmosphere?They used carbon dioxide and released oxygen in photosynthesis8.26386What is the composition of our atmosphere today?Nitrogen about 78%, Oxygen 21%, 1% other gases8.24387Name 3 greenhouse gasesCarbon dioxide, methane and water vapour8.24388What is the greenhouse effectGreenhouse gases absorb heat radiated from the earth and release it keeping the earth warm8.26b389Name 2 effects of global warmingPolar ice caps melting, sea levels rising8.18390Where did the gases that formed our early atmosphere come from?They were produced by volcanic activity.8.19391What gas, in today's atmosphere was missing from our early atmosphere?oxygen8.25392What does correlation mean?There is a link between them. (eg. As one increases so does the other)8.22393When did oxygen begin to be formed in our atmosphere?When the first plants began photosynthesising8.24394What do greenhouse gases do?Trap heat in our atmosphere8.26395Name one man made cause of the greenhouse effectDeforestation8.25396What has happened to the amount of carbon dioxide in our atmosphere in the last 200 years?It has increased8.25397What human activity might have increased the amount of carbon dioxide in our atmosphere?Burning fossil fuels8.25398What human activity, other than burning fossil fuels, might have increased the amount of carbon dioxide in our atmosphere?Respiration (as population increases so does this)?399If a sample of the atmosphere is reacted with copper, what gas will react?Oxygen?400If all the oxygen is removed from a sample of the atmosphere how much is removed?21%Topic 5 – Transition Metals5.6401What is an alloy?A mixture of two or more elements, at least one of which is a metal5.5402Give a reason for alloying a metalTo make it harder, to make it less reactive5.5403Explain why alloys can be harder than pure metals Different size of atoms disturb the layers to stop them sliding over each other5.1404What are the typical properties of transition metals?High melting point, high density, form coloured compounds, act as catalysts for particular reactions.5.3405How can rusting of iron be prevented?By excluding water and oxygen 5.3406What can you exclude to reduce rusting of iron.water and oxygen5.3407How else can rusting of iron be prevented?By sacrificial protection5.3c408What is sacrificial protection?Coating the metal in a more reactive metal that will react in preference to the one you are trying to protect5.4409What is electroplating?Using electrolysis to coat the metal to be protected in a thin layer of another metal5.4410Why is electroplating used?It improves appearance and increases resistance to corrosion.5.6411Why is iron alloyed to make steelto improve resistance to corrosion and increase strength.5.7412How does alloying gold increase its strengthThe different sized atoms mixed with the gold atoms disrupt the layers of identical gold atoms and stop them rolling over one another.5.7413What properties of gold make it suitable for its usesunreactive - jewellery lasts well5.7414What is copper used for?wires - because it is a good conductor, water pipes - because it is unreactive5.2415What causes corrosion of metals?oxidation5.7416What is aluminium used for?Drinks cans - lightweight, ladders - low density5.7417What is brass used for?Door fittings - unreactive, attractive5.7418What is magnalium used for?Scientific instruments - increased malleable, lower density than aluminium5.2419What is another name for oxidation of metals?corrosion5.1420What are irons properties?High melting point, high density, form coloured compounds, act as catalysts for particular ic 5 – Equilibrium5.19421What is the Haber process?A reversible reaction between nitrogen and hydrogen forming ammonia5.21422In an industrial reaction why would you carry it out at a high temperature even if this would shift the equilibrium to the left hand side and reduce percentage yield?To increase the rate of the reaction, saving time5.22423What elements do fertilisers contain?Nitrogen, phosphorus and potassium (NPK)5.22424What are fertilisers used for?To promote plant growth5.23425What is formed when ammonia reacts with nitric acid?Ammonium nitrate5.23426Why is ammonium nitrate a good fertiliser?NH4NO3, contains 2 nitrogen atoms per molecule5.24427How would you make ammonium sulphate?From ammonia and sulfuric acid5.20a428How will an increase in temperature affect the rate of attainment of equilibrium?Equilibrium will be reached quicker.5.20a429How will an decrease in temperature affect the rate of attainment of equilibrium?Equilibrium will be reached slower.5.20b430How will an increase in pressure affect the rate of attainment of equilibrium?Equilibrium will be reached quicker.5.20b431How will an decrease in pressure affect the rate of attainment of equilibrium?Equilibrium will be reached slower.5.20c432How will an increase in concentration affect the rate of attainment of equilibrium?Equilibrium will be reached quicker.5.20c433How will an decrease in concentration affect the rate of attainment of equilibrium?Equilibrium will be reached slower.5.20d434How will adding a catalyst affect the rate of attainment of equilibrium?Equilibrium will be reached quicker.5.21b435Why would you choose a lower/medium pressure when a high pressure would give a better yield?To reduce costs and risk.5.21b436Why would you choose a high temperature when a low temperature would give a better yield?To increase rate of reaction5.21b437Why would you use a catalyst in an industrial reaction?To increase rate of reaction and reduce costs.5.23438Write a word equation for the reaction of ammonia and nitric acid.ammonia + nitric acid --> ammonium nitrate 439Why does increasing temperature increase rate at which equilibrium is reached?There are more frequent collisions between particles so the rate of reaction increases.440Why does increasing pressure increase rate at which equilibrium is reached?There are more frequent collisions between particles so the rate of reaction ic 5 – Fuel Cells441What is a chemical cell?A unit which contains chemicals which produce electricity through a reaction5.25442What are the main components of a chemical cell?An anode, a cathode and an electrolyte443What is an electrolyte?A solution containing ions which allows current to flow.5.25444What does the potential difference of a cell depend on?The type of electrode and the electrolyte.5.25445What is a battery?Two or more cells connected in series5.25446What happens to the electrodes in a chemical cell?The more reactive metal depletes and the less reactive one increases in size.5.25447In non-rechargeable cells, why do the chemical reactions stop over time?One of the reactants becomes used up.5.25448How can certain cells be recharged?Applying an external electric current5.25449How does the reactivity of the metal electrodes affect the size of the potential difference?The greater the difference in reactivity, the greater the potential difference.5.26450What is a fuel cell?A cell which uses a fuel and oxygen (or air) to generate electricity.5.26451What are the products in a hydrogen fuel cell?Water5.26452State three advantages of hydrogen fuel cellsDo not need to be recharged, no pollutants are produced, can be different sizes for different uses5.26453State three disadvantages of hydrogen fuel cellsHydrogen is highly flammable, hydrogen is sometimes produced through non-renewable means, hydrogen is difficult to store5.26454Complete the equation which occurs at the negative electrode of a hydrogen fuel cell 2H? + 4OH? →4H?O + 4e?5.26455Complete the equation which occurs at the positive electrode of a hydrogen fuel cell O? + 2H?O →4OH?5.26456What is the overall reaction occurring in a hydrogen fuel cell?O? + 2H? → 2H?O 5.27457Does a hydrogen fuel cell produce greenhouse gases?yes water is a greenhouse gas5.27458Does a hydrogen fuel cell produce any carbon emissions?no, only product Is water, but sometimes CO2 is produced making the hydrogen fuel.5.27459Why is hydrogen difficult to store?It is a highly flammable gas so needs pressurised tanks460What other fuels can fuel cells run on?methanolTopic 9 Qualitative Analysis9.2461What is a flame test?A test to identify metal ions (cations)9.2462What is the colour of the flame produced from a lithium containing compound?Crimson9.2463What is the colour of the flame produced from a copper containing compound?Green9.2464What is the colour of the flame produced from a sodium containing compound?Yellow9.2465What is the colour of the flame produced from a potassium containing compound?lilac9.2466What is the colour of the flame produced from a calcium containing compound?Orange-red9.3467Other than flame tests, how can metal ions be identified?Use of sodium hydroxide9.3468Which solutions produce white precipitates on addition of sodium hydroxide?Solutions containing aluminium, calcium ions9.3469How can a solution of aluminium ions be distinguished from calcium ones?Its precipitate will dissolve in excess sodium hydroxide9.3470What is the colour of the precipitate formed from the addition of sodium hydroxide to a solution containing copper (II) ions?Blue9.3471What is the colour of the precipitate formed from the addition of sodium hydroxide to a solution containing iron(II) ions?Green9.3472What is the colour of the precipitate formed from the addition of sodium hydroxide to a solution containing iron(III) ions?Brown9.5a473What is the test for carbonates?Add an acid to generate carbon dioxide gas9.5c474What is the test for halides?Add silver nitrate and nitric acid to generate a solid silver halide precipitate9.5c475What are the colours of the silver halides?Silver chloride white, silver bromide cream, silver iodide yellow9.5b476What is the test for sulphate ions?Add barium chloride and hydrochloric acid, forms white precipitate9.8477How do we test for ammonia gas?Add damp red litmus paper it will turn blue.9.8478What are the three advantages of instrumental methods?They are accurate (gives correct results), sensitive (only needs a small sample to work), rapid (a lot faster than other tests)9.9479What is flame emission spectroscopy?An instrumental analysis tool for identifying metal ions9.9480How is flame emissions spectroscopy carried out?Sample placed in a flame, light emitted is passed through a spectroscope to give a spectrum which can be compared to a referenceTopic 9 Hydrocarbons9.15481How do you test for an alkene? React it with bromine water. 9.13482What is the general formula for alkenes?CnH2n9.11483What does unsaturated means?Contains double bonds (which could become C-H bonds)9.12484What are the first four alkenes?Ethene, propene, butene, pentene9.16485How is the combustion of alkenes different to combustion of alkanes?Alkenes usually react by incomplete combustion so burn with smoky flames9.11486What type of hydrocarbon are alkanes?saturated9.11487What is a hydrocarbon?a molecule made of hydrogen and carbon atoms only.9.10.488What are the first four alkanes?Methane, Ethane, propane, and butane9.12489What functional group do all alkenes contain?C=C9.10.490What is the general formula for alkanes?CnH2n+29.15491What is the colour change when an alkene reacts with bromine water?The bromine water turns from orange to colourless9.15492What is the colour change when an alkane is added to bromine water?There is no colour change it remains orange.9.15493Which substance will decolourise bromine water, propane or propene?Propene9.16494What is produced when an alkane is combusted?carbon dioxide and water9.16495Write a balanced equation for the combustion of methane, CH4.CH4 + 2O2 --> CO2 + 2H2O9.16496What is happening to the hydrocarbon when it is being combusted?It is being oxidised9.13497Why are alkenes unsaturated compounds?They contain a C=C double bond9.11498Why are alkanes saturated compounds?They contain no C-C double bond. They have only single bonds9.12499How are but-1-ene and but-2-ene different?The position of the double bond. In but-1-ene between C's 1 & 2. In but-2-ene between carbons 2 & 39.11500Is di-chloroethane a hydrocarbon?No it does not contain just carbon and hydrogen atoms. It also contains chlorine ic 9 Alcohols and Carboxylic acids9.24501What functional group do all alcohols have?OH9.26502Name and draw the first four alcoholsMethanol, ethanol, propanol, butanol (ethanol pictured)503What happens when an alcohol reacts with sodium?It forms a sodium salt (e.g. sodium ethoxide from ethanol) and releases hydrogen gas.504What are the products of a combustion reaction involving an alcohol and oxygen?Carbon dioxide and water505Write a symbol equation for the reaction of methanol/ethanol/propanol/butanol with oxygenE.g. CH?CH?OH + 5O? → 2CO? + 3H?O506Do alcohols dissolve in water?Yes, they form neutral solutions9.31507How do alcohols react with oxidizing agents?They turn into carboxylic acids508What are the main uses of alcohols?Solvents, ethanol used as drinking alcohol and a biofuel9.33509What is fermentation?The process of turning glucose (a natural sugar) into ethanol9.33510What is required for natural fermentation?Yeast9.3511What functional groups do all carboxylic acids have?COOH9.29512Name and draw the first four carboxylic acidsMethanoic acid, ethanoic acid, propanoic acid, butanoic acid (image is ethanoic acid)513Why are carboxylic acids weak acids?Not all their molecules ionise when in water9.31514What is made when ethanol is oxidised?Ethanoic acid9.28515How do you compare the energy released by alcohols when they are combusted.Burn the alcohol, use the energy to heat water. Measure the temperature change of the water. Calculate the temperature change caused per gram of alcohol burnt.9.27516What is made when ethanol is dehydrated?An alkene9.34517How can ethanol be concentrated?Distillation9.32518Why do alcohols have the same type of reactions?They are part of the same homologous.9.27519What group do molecules with an -OH belong to?alcohols9.27520What group do molecules with an -COOH belong to?carboxylic acidTopic 9 Polymers9.19521What is the monomer in poly(ethene)?ethene9.18522What is polymerisation?The process of using small molecules (monomers) to make long chain molecules (polymers)9.18 & 9.22523What are the two types of polymerisation?Addition and condensation9.18524What monomers are involved in addition polymerisation?Alkenes9.2525How do we draw polymers?In round brackets with an n [poly(ethene) is shown]9.22526What type of monomers are involved in condensation polymerisation?Ones with two functional groups (like a diol)9.22527What are the products of condensation polymerization?A polymer and a small molecule (usually water)9.19528What is the polymer made from chloroethene monomer?poly(chloroethene)9.19529What is the monomer in poly(tetrafluoroethene) (PTFE)?tetrafluoroethene9.21530What is a use of poly(ethene)?carrier bags9.21531What is a use of poly(propene)?drain pipes9.21532What is a use of poly(chloroethene)?clothing9.21533What is a use of PTFE?Non stick coatings on pans9.20.534What does the repeating unit for the polymer made of propene look like?(CH3CH-CH)-9.25c535What is formed from different amino acids combined in one chain?Proteins9.25a536What does DNA stand for?Deoxyribonucleic acid9.25a537What is DNA?A large molecule containing genetic information9.25a538What is the structure of DNA?Two polymer chains made from nucleotides in the form of a double helix9.25539Name four naturally occurring polymersDNA, proteins, starch, cellulose9.25b540What monomers are starch and cellulose made of?GlucoseTopics 1 Calculations with Mass and Topic 5 CalculationsAr = Sum of (atomic mass x percentage abundance) / 100Ar - relative atomic massNo unitsMr = Sum of (Ar atoms x number of atoms of each element)Mr – relative molecular/formula massNo unitsm = n x Mrm – mass (g)n – amount of substance (mol)M – molar mass (g mol-1)n = V / Vmn – amount of gas (mol) at RTP (room temperature and pressure)V – volume of gas (dm3)Vm – molar volume of gas (24.0 dm3)c = n / Vc – concentration (mol dm-3)n – amount of substance (mol)V – volume of solution (dm3)c = m / Vc – concentration (g dm-3)m – mass (g)V – volume of solution (dm3)c(mass) = c(mol) x Mc(mass) – concentration (g dm-3)c(mol) – concentration (mol dm-3)M – molar mass (g / mol)pV = nRTp – pressure (Pa)V – volume (m3)n – amount of substance (mol)R – molar gas constant (8.314 JK-1mol-1)T – temperature (K)percentage yield = ( actual yield / theoretical yield ) x 100%Atom economy = [ (mass of desired products in balanced equation) / (total mass of products in balanced equation) ] x 100 ................
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