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ElementsElements are sometimes called the building blocks of life. The periodic table (a copy is on the next page) contains all the known elements and each one has a name and symbol.Task 1Use the Periodic Table to write down the symbols of the following elements.a) Fluorinef) Palladiumb) Lithiumg) Leadc) Strontiumh) Goldd) Xenon i) Tungstene) Cobaltj) MercuryTask 2Use the Periodic Table to write down the names of the following elements.a) Rnf) Agb) Heg) Snc) Pth) Vd) Zni) He) Csj) RbChallenge Task 1What are the rules for writing the symbols of the elements?Challenge Task 2Research what the definition of an element is.Challenge Task 3Research who Dmitri Mendeleev is.Challenge Task 3Use the symbols of the elements to write down as many words as you can that contain seven or more letters. You can use the symbols as many times as you want in each word.The Periodic TableRelative Atomic Mass and Atomic NumberEach element also has two numbers. The top number is called the relative atomic mass (or Ar for short) and the bottom number is called the atomic number. These are shown in the key on the previous page. These numbers tell you how many protons, electrons and neutrons are found in each atom of each element.Number of protons = atomic numberNumber of electrons = atomic numberNumber of neutrons = relative atomic mass – atomic numberTask 1Use this information (and the periodic table) to answer the following.State the number of protons in an atom of magnesium.State the number of protons in an atom of bromine.State the number of electrons in an atom of carbon.State the number of electrons in an atom of copper.State the number of neutrons in an atom of iodine.State the number of neutrons in an atom of rhenium.Task 2Name the element that doesn’t have any neutrons in its atoms.Task 3State how the elements are arranged in the Periodic Table.Challenge Task 1The charge of a proton is +1 and the charge of an electron is –1. Use this information to explain why all atoms are neutral (have no charge) overall.Challenge Task 2The two atoms shown are the two isotopes of chlorine.Use this information to state what the definition of an isotope is.Chemical FormulaA chemical formula shows the number and type of each particle found in a substance.ExamplesSodium chloride has the formula NaCl.This tells us there is one sodium (Na) particle and one chlorine (Cl) particle.Calcium bromide has the formula CaBr2.This tells us there is one calcium (Ca) particle and two bromine (Br) particles. Aluminium oxide has the formula Al2O3.This tells us there are two aluminium (Al) particles and three oxygen (O) particles. Notice that if there is a number in a formula then it is written after the particle and below.Task 1Write the name and number of each particle in the following formulae. a) NaFe) H2SO4b) MgBr2f) Rb2CO3c) K2Og) CH3COOHd) Fe2O3h) C6H4N2C6H4NH2Task 2Nitric acid is an acid used to make fertilisers. Each molecule of nitric acid contains one atom of hydrogen, one atom of nitrogen and three atoms of oxygen. Write the formula of nitric acid.Task 3Phosphoric acid is an acid that is found in some drinks. Each molecule of phosphoric acid contains three atoms of hydrogen, one atom of phosphorus and four atoms of oxygen. Write the formula of phosphoric acid.If the formula contains a bracket with a number after it then this tells you to multiply everything inside the bracket by the number.ExamplesMagnesium hydroxide has the formula Mg(OH)2.This tells us there is one magnesium (Mg) particle, two oxygen (O) particles and two hydrogen (H) particles. Calcium nitrate has the formula Ca(NO3)2.This tells us there is one calcium (Ca) particle, two nitrogen (N) particles and six oxygen (O) particles. Task 4Write the name and number of each particle in the following formulae. a) Be(OH)2e) Al2(CO3)3b) Zn(NO3)2f) Fe2(SO4)3c) Fe(OH)3g) CuSO4(H2O)3d) (NH4)2SO4h) C6H2(NO2)3CH3Challenge Task 1All the formulae in these tasks are of compounds. State what the definition of a compound is.Challenge Task 2Use the information in the table to match up each circle with each element then use your answers to draw a diagram of CO2 and NH3.Relative Formula MassA relative formula mass (or Mr for short) tells us the total mass of all the particles found in each formula of a substance. To be able to calculate the Mr we need to know the mass of the individual particles, which is called the relative atomic mass (or Ar for short). The Ar of each atom can be found using the periodic table. Each element has got two numbers and the Ar is the top number.Example19 FThis shows that the Ar of fluorine (F) is 19How to calculate the Mr of a substanceWork out how many particles there are of each element and then multiply by the Ar of that element.ExamplesSodium chloride has the formula NaCl. This tells us there is one sodium (Na) particle and one chlorine (Cl) particle.23Na and 35.5Cl are the Ar valuesNa x 1 = 23 x 1 = 23Cl x 1 = 35.5 x 1 = 35.5Mr of NaCl = 23 + 35.5 = 58.5Calcium chloride has a formula CaCl2. This tells us there is one calcium (Ca) particle and two chlorine (Cl) particles.40Ca and 35.5Cl are the Ar valuesCa x 1 = 40 x 1 = 40Cl x 2 = 35.5 x 2 = 71Mr of CaCl2 = 40 + 71 = 111Calcium nitrate has a formula Ca(NO3)2. This tells us there is one calcium (Ca) particle, two nitrogen (N) particles and six oxygen (O) particles.40Ca, 14N and 16O are the Ar valuesCa x 1 = 40 x 1 = 40N x 2 = 14 x 2 = 28O x 6 = 16 x 6 = 96Mr of Ca(NO3)2 = 40 + 28 + 96 = 164TaskCalculate the Mr of the following compounds.a) NaFf) Ca(OH)2k) Zn(NO3)2b) MgBr2g) Fe2(SO4)3l) Al2(SO4)3c) K2Oh) Al2(CO3)3m) (NH4)2CO3d) Fe2O3i) (NH4)2SO4n) C6H3(NO2)3e) H2SO4j) Cu(NO3)2o) C6H4(NH2)N2C6H3(OH)2Challenge TaskIn the following formulae there is a mystery particle, X. By finding the relative atomic mass of X, identify the name and symbol of X. XO (Mr XO = 25)XO2 (Mr XO2 = 64)X2O3 (Mr X2O3 = 160)O = oxygen for each exampleHomework 1Write the name and number of each particle in the following formulae. (2 each)a. KI b. SrO c. ZnCl2 d. CoCO3 e. (NH4)2SO4Calculate the relative formula mass (Mr) of each of the following. (2 each)a. CuSO4 b. Al2(CO3)3 c. Fe(OH)2Calculate the relative atomic mass (Ar) of the unknown particle X in the following. (2 each)a. XNO3 Mr = 170 b. X2O5 Mr = 182Percentage (%) by MassTo calculate the percentage (%) by mass of a certain particle (Z) in a substance you use the following equation:Remember that Mr is the relative formula mass.% by mass of Z = total mass of particles of Z x 100 MrExamplesCalculate the % by mass of hydrogen (H) in CH4. In this example, Z is hydrogen (H) and you need to calculate the Mr of CH4.Total mass of H (Z)Remember that you have already calculated some Mr values.Total mass of CH4 (Mr)4 x 1 = 4(1 x 12) + (4 x 1)= 12 + 4= 16% by mass of hydrogen (H) = 4/16 x 100 = 25 %Calculate the % by mass of oxygen (O) in CaCO3. In this example, Z is oxygen (O) and you need to calculate the Mr of CaCO3.Total mass of O (Z)Total mass of CaCO3 (Mr)3 x 16 = 48(1 x 40) + (1 x 12) + (3 x 16)= 40 + 12 + 48= 100% by mass of oxygen (O) = 48/100 x 100 = 48 %Task 1Calculate the % by mass of hydrogen (H) in the following compounds. Give your answer to one decimal place if it isn’t a whole number.H2ONaOHC2H6NaHCO3H2CO3(NH4)2CO3Task 2Calculate the % by mass of oxygen (O) in the following compounds. Give your answer to one decimal place if it isn’t a whole number.CO2Li2OKNO3CH3COOHH2SO4(NH4)2SO4Challenge Task 1Calculate the percentage (%) by mass of water in CuSO4.5(H2O). Give your answer to one decimal place.Challenge Task 2Calculate the value of x in BaCl2.xH2O given that the Mr is 244.Challenge Task 3Calculate the value of x in Ca(NO3)2.xH2O given that the Mr is 236.Ionic FormulaThe formulae for some common ions are shown in the table.Task 1State what the definition of an ion is.Task 2What do you think “(II)” stands for after copper?Task 3State why iron is different to all the other names in the table.Task 4Why are the ammonium, carbonate, hydroxide, nitrate and sulfate ions different to all the others?Task 5The symbols of the five ions from task 4 now need to be written using a bracket. The letters are written inside the bracket and everything else remains outside. Two have been done for you.ExamplesThe ammonium ion, NH4+, is now written as (NH4)+The carbonate ion, CO32–, is now written as (CO3)2–How to write an ionic formula Write the name of the two ions (one positive and one negative).Write the symbols (and charges) of the two ions close to each other.Rub out the + and – signs. Swap over the numbers that are left then write them at the bottom.If these numbers are the same then rub them out.Important rule – never change the inside of a bracket.ExamplesSodium Iodide: Na+ I– = NaIPotassium oxide: K+ O2– = K2OCalcium oxide: Ca2+ O2– = CaOAluminium oxide: Al3+ O2– = Al2O3Calcium nitrate: Ca2+ (NO3)– = Ca(NO3)2Task 6Write the chemical formula for each of the following compounds.a) Sodium chlorided) Calcium fluorideg) Lithium Iodideb) Magnesium bromidee) Copper(II) oxideh) Aluminium fluoridec) Potassium oxidef) Silver bromidei) Iron(III) oxideTask 7Write the chemical formula for each of the following compounds.a) Calcium hydroxided) Iron(II) carbonateg) Potassium hydroxideb) Sodium sulfatee) Ammonium hydroxideh) Aluminium nitratec) Ammonium chloridef) Zinc nitratei) Iron(III) sulfateChallenge Task 1The formula of lithium sulfide is Li2S. Write down the symbol and charge of the sulfide ion.Challenge Task 2Use your answer from challenge task 1 to write the formula of aluminium sulfide.Challenge Task 3The formula of sodium hydrogencarbonate can be written as NaHCO3. Write down the symbol and charge of the hydrogencarbonate ion.Challenge Task 4Use your answer from challenge task 3 to write the formula of magnesium hydrogencarbonate.Challenge Task 5The formula of phosphoric acid can be written as H3PO4. Write down the symbol and charge of the phosphate ion.Challenge Task 6Use your answer from challenge task 5 to write the formula of calcium phosphate.Chemical Reactions and MassReactants are turned into products in chemical reactions. The substances at the start are called the reactants because they react together. The substances that are made are called the products because they are produced.reactants productsMass is conserved in all chemical reactions. This means the total mass of the reactants will equal the total mass of the products. This happens because no particles are destroyed and no new particles are made.ExampleSodium (2.3 g) reacts with fluorine (38.0 g) to produce sodium fluoride.sodium + fluorine sodium fluorideThe mass of sodium fluoride produced = 2.3 g + 38.0 g = 40.3gTask 1For mass to be conserved in all chemical reactions, explain what has happened to the particles.Task 2The reactants, A and B, react together to produce a product, C.A + B CUse your knowledge of the conservation of mass to calculate the missing masses in the table.ReactionMass of A (g)Mass of B (g)Mass of C (g)1142925.84.63316449.512.350.280.30Task 3The reactants, A and B, react together to produce the products, C and D.A + B C + DUse your knowledge of the conservation of mass to calculate the missing masses in the table.ReactionMass of A (g)Mass of B (g)Mass of C (g)Mass of D (g)16811223191733.14.85.6414.18.39.2526.917.423.5Task 4Magnesium ribbon is heated in a Bunsen flame. The magnesium burns with a bright white light, as it reacts with oxygen gas in the air, to form magnesium oxide. If the mass of magnesium used was 2.4 g, explain whether the mass of the magnesium oxide formed be greater than, less than or equal to 2.4 g.Challenge Task 1The reactants, A and B, react together to produce the products, C, D and E.A + B C + D + EThe mass of B that reacted was three times the mass of A and the mass of E produced was half of the masses of C and D. If 7.5 g of A was used, calculate the masses of B, C, D and E.Challenge Task 2Write down some ways in which you would know a chemical reaction is taking place in a beaker.Challenge Task 3In an experiment, 100 g of a white solid, calcium carbonate (CaCO3) are strongly heated. At the end of the experiment, the mass of the white solid remaining, calcium oxide (CaO), was 56 g. Give a reason why the mass appears to have decreased in the reaction. Percentage (%) YieldThe percentage (%) yield of a reaction tells us how much product has been produced. To calculate the % yield you use the following equation:The mass of product expected is sometimes called the theoretical yield.% yield = mass of product obtained x 100 mass of product expectedExampleIn a reaction, 25 g of product were expected but only 5 g were obtained.% yield = 5/25 x 100 = 20 %Task 1State what the maximum % yield of a reaction can be.Task 2Calculate the % yields of the following reactions. Give your answer to one decimal place if it isn’t a whole number.ReactionMass of product obtained (g)Mass of product expected (g)13122152534.67.9415.419.7567.884.3Challenge Task Give some reasons why the % yield of a reaction might be lower than expected.Homework 2Calculate the percentage (%) by mass of carbon (C) in each of the following, giving your answer to one decimal place. (2 each)a. C3H8 b. CH3CO2C2H5Write the ionic formula for each of the following substances. (1 each)a. Calcium iodide b. Iron(III) nitrate c. Ammonium sulfate d. Magnesium oxideIn a chemical reaction mass is conserved. Explain what this means. (2)0.72 g of magnesium are completely reacted with oxygen gas to produce 1.20 g of magnesium oxide as the only product. Calculate the mass of oxygen that reacted with the magnesium. (2)18.4 g of sodium react completely with 28.4 g of chlorine to produce sodium chloride as the only product. The yield of sodium chloride produced was 50 %. Calculate the mass of sodium chloride produced. (2)Balancing EquationsA chemical reaction can be represented by a balanced equation.ExamplesFe + S FeSMgCO3 Mg + CO22 Na + Cl2 2 NaCl2 NaI + Br2 2 NaBr + I2There are numbers in front of some of the substances to balance the equation.Task 1By looking at the above examples, explain what is meant by a balanced equation.Task 2State which of the following equations are balanced.Li2CO3 Li2O + CO22 K + O2 2 K2OCa + 2 Cl2 CaCl2Mg + H2SO4 MgSO4 + H22 Na + 2 H2O 2 NaOH + H2Task 3The following equations all need to be balanced by placing numbers (except for the number 1) in the gaps. Write out each equation with the correct number in each gap.Ca + ___HCl CaCl2 + H2___Na + O2 ___Na2O___Li + Cl2 ___LiCl___H2O ___H2 + O2___Fe + ___Br2 ___FeBr3___Al2O3 ___Al + ___O2Challenge Task 1The following equations all need to be balanced by placing numbers (except for the number 1) in the gaps. Write out each equation with the correct number in each gap.Ba3N2 + ___HF ___BaF2 + ___NH3___CaCl2 + ___Na3PO4 Ca3(PO4)2 + ___NaCl___Si2H2 + ___O2 ___SiO2 + ___H2OChallenge Task 2Magnesium hydroxide reacts with nitric acid (HNO3) to produce magnesium nitrate and water. Write the balanced symbol equation for this reaction.Moles and Standard FormIn chemistry, numbers of particles are counted in moles. A mole simply refers to a certain number of particles. Other words are used to represent a certain number. For example:1 dozen = 121 score = 201 gross = 1441 mole = 600,000,000,000,000,000,000,000This number is called the Avogadro constant. As the number shows, a mole is a huge number which is why it is written in standard form:1 mole = 6 x 1023TaskWrite the answers to the following in standard form.The number of seconds in an hour.The number of seconds in a day.The number of seconds in a year.The number of seconds in 100 years.The number of seconds in 1 million years.The number of seconds in 100 million years.Calculating Moles of AtomsTo calculate the number of moles of individual atoms you use the following equation:Remember that Ar is the relative atomic mass.moles = mass (g) ArExampleCalculate the number of moles in 46 g of sodium.mass of sodium = 46 gAr of sodium = 23moles = 46/23 = 2TaskCalculate the number of moles of each the following atoms.28 g of lithium280 g of iron591 g of gold59.5 g of tin0.4 g of argonCalculating Moles of CompoundsIf you are not dealing with individual atoms then to calculate the number of moles you use the following equation:Remember that Mr is the relative formula mass.moles = mass (g) MrThis is the equation you use to calculate the number of moles of a compound.ExampleCalculate the number of moles in 54 g of water (H2O).mass of water = 54 gMr of water = 1 + 1 + 16 = 18moles = 54/18 = 3TaskCalculate the number of moles of each the following compounds.28 g of carbon monoxide (CO)192 g of sulfur dioxide (SO2)119 g of hydrogen peroxide (H2O2)16.2 g of hydrogen bromide (HBr)8.4 g of potassium hydroxide (KOH)Challenge TaskCalculate the number of moles of the following substances. Give your answer to one decimal place if it isn’t a whole number.1.0 kg of glucose (C6H12O6)0.3 kg of sulfuric acid (H2SO4)4 x 10-2 g of magnesiumCalculating Masses using MolesYou can rearrange the equation on the previous page to calculate the mass of a substance.For individual atomsFor everything else, such as compoundsmass (g) = moles x Armass (g) = moles x MrExamplesCalculate the mass of 4 moles of sodium.moles = 4Ar of sodium = 23mass = 4 x 23 = 92 gCalculate the mass of 2 moles of water (H2O).moles = 2Mr of water = 1 + 1 + 16 = 18mass = 2 x 18 = 36 gTaskCalculate the mass (in g) of each the following substances.3.4 moles of helium2 moles of silver0.5 moles of rubidium1.5 moles of aluminium oxide (Al2O3)0.8 moles of nitric acid (HNO3)Challenge Task 1Identify each of the following elements using the information given.24 g and 0.5 moles7 g and 0.1 moles108 g and 9 moles9 g and 0.2 moles0.1 kg and 5 molesChallenge Task 2Calculate the number of oxygen atoms present in 2 moles of water (H2O).Challenge Task 3Calculate the number of hydrogen particles present in 0.5 moles of hydrogen bromide (HBr).HintTo answer challenge tasks 3 and 4 you need to use the Avogadro constant.Simplest FormulaA simplest formula shows the smallest ratio of particles in a chemical formula. Example 1The chemical formula of ethane is C2H6The simplest formula of ethane is CH3The numbers in a simplest formula have to be whole numbers which means the chemical formula and simplest formula might be the same.Example 2The chemical formula of carbon dioxide is CO2The simplest formula of carbon dioxide is also CO2Task 1Write the simplest formula of each of the following compounds.Water (H2O)Butane (C4H10)Pentane (C5H12)Glucose (C6H12O6)Ethanoic acid (CH3COOH)To calculate a simplest formula using given masses you need to follow the following steps:Remember that moles = mass ArStep 1Calculate the moles of each element.Step 2Divide each answer from step 1 by the smallest number.Step 3Write the simplest formula.Example 1Calculate the simplest formula of a compound that contains 20 g of calcium and 80 g of bromine.Step 1moles of Ca = 20/40 = 0.5moles of Br = 80/80 = 1Remember that moles = mass ArStep 2The smallest number is 0.5 so divide the answers in step 1 by 0.5Ca = 0.5/0.5 = 1Br = 1/0.5 = 2Step 3The simplest formula is CaBr2Example 2Calculate the simplest formula of a compound that contains 24 g of magnesium and 16 g of oxygen.Step 1moles of Mg = 24/24 = 1moles of O = 16/16 = 1Remember that moles = mass ArStep 2The smallest number is 1 so divide the answers in step 1 by 1Mg = 1/1 = 1O = 1/1 = 1Step 3The simplest formula is MgOTask 2Calculate the simplest formula of each of the following.A compound that contains 24 g of magnesium and 71 g of chlorine.A compound that contains 23 g of sodium and 8 g of oxygen.A compound that contains 15.6 g of potassium and 32 g of bromine.Sometimes you have to calculate a mass first before you can calculate the simplest formula.ExampleAn oxide of lithium, which had a mass of 45 g, contained 21 g of lithium.The mass of oxygen in the oxide of lithium must be 45 g – 21 g = 24 g.Now the steps are carried out:Step 1moles of Li = 21/7 = 3moles of O = 24/16 = 1.5Step 2The smallest number is 1.5 so divide the answers in step 1 by 1Li = 3/1.5 = 2O = 1.5/1.5 = 1Step 3The simplest formula is Li2OTask 3An oxide of copper, which had a mass of 71.5 g, contained 63.5 g of copper. Calculate the mass of oxygen in the oxide of copper and then calculate the simplest formula.Task 4A chloride of iron, which had a mass of 32.5 g, contained 11.2 g of iron. Calculate the mass of chlorine in the chloride of iron and then calculate the simplest formula.Challenge Task Calculate the simplest formula of compound that contains 120 g of carbon and 25 g of hydrogen.Homework 3The following equations all need to be balanced by placing numbers (except for the number 1) in the gaps. Write out each equation with the correct number in each gap. (1 each)___Rb + O2 ___Rb2O___Li + Br2 ___LiBrState what number a mole is equal to. (1)Calculate the number of moles in each of the following. (2 each)7 g of Si5 g of NaOH0.5 g of MgOCalculate the mass (in g) in each of the following. (2 each)2 moles of Ne0.5 moles of CO20.2 moles of NH3Write the simplest formula of the following. (3)C2H6C3H6C2H5Molar RatiosChemical reactions can be represented by a balanced symbol equation. This shows the ratio of the number of moles (the molar ratio) of reactants to products.ExampleMg + 2 HCl MgCl2 + H2This balanced symbol equation shows that 1 mole of Mg reacts with 2 moles of HCl to produce 1 mole of MgCl2 and 1 mole of H2. Notice that if there is 1 mole of any substance then the number 1 doesn’t need to be written in front of its symbol or formula in the balanced symbol equation.The molar ratios of this reaction, which are the simplest possible, are shown below. 1 : 2 1 : 1Task 1Look at the following ratios and write the simplest ratio possible.1 : 34 : 212 : 31.5 : 7.50.375 : 0.125Task 2Use your knowledge of ratios to answer the following.The ratio of apples to oranges is 1 : 1. State the number of oranges if there are 8 apples.The ratio of boys to girls is 2 : 1. State the number of boys if there are 12 girls.The molar ratio of sodium to lithium is 1 : 1. State the number of moles of sodium if there are 0.2 moles of lithium.The molar ratio of water to carbon dioxide is 1 : 2. State the number of moles of water if there are 0.5 moles of carbon dioxide.The molar ratio of carbon to oxygen is 4 : 2. State the number of moles of carbon if there are 0.8 moles of oxygen.Using Molar RatiosYou can be asked to calculate one of the following using molar ratios:The mass of a product when the mass of a reactant is knownThe mass of a reactant when the mass of a product is knownHowever, the same steps are followed for both:KnowMolar Ratio(Know : Find)FindThe moles of the “know” (reactant or product) will be calculated hereFor individual atoms use:moles = mass/ArFor everything else use:moles = mass/MrThis is the molar ratio – you use the numbers in front of the “know” and “find” in the balanced symbol equationThis will allow you to calculate the moles (and then the mass) of the “find”The mass of the “find” (reactant or product) will be calculated hereFor individual atoms use:mass = moles x ArFor everything else use:mass = moles x MrExample 1Calculate the mass of MgCl2 that can be produced from 12 g of Mg.Mg + 2 HCl MgCl2 + H2KnowMolar Ratio(Know : Find)Findmass of Mg = 12 gAr of Mg = 24moles of Mg = mass/Ar = 12/24 = 0.5Mg : MgCl2Remember that no number in front means 1 mole1 : 10.5 : 0.5This tells us the moles of MgCl2 are also 0.5moles of MgCl2 = 0.5Mr of MgCl2 = 95mass of MgCl2 = moles x Mr = 0.5 x 95 = 47.5 gExample 2Calculate the mass of Na that is needed to produce 0.62 g of Na2O.4 Na + O2 2 Na2OKnowMolar Ratio(Know : Find)Findmass of Na2O = 0.62 gMr of Na2O = 62moles of Na2O = mass/Mr = 0.62/62 = 0.01Na : Na2O4 : 22 : 10.02 : 0.01This tells us the moles of Na are 0.02moles of Na = 0.02Ar of Na = 23mass of Na = moles x Ar = 0.02 x 23 = 0.46 gExample 3Calculate the mass of H2 that can be produced from 4.6 g of Na.2 Na + 2 H2O 2 NaOH + H2KnowMolar Ratio(Know : Find)Findmass of Na = 4.6 gAr of Na = 23moles of Mg = mass/Ar = 4.6/23 = 0.2Na : H2Remember that no number in front means 1 mole2 : 10.2 : 0.1This tells us the moles of H2 are 0.1moles of H2 = 0.1Mr of H2 = 2mass of H2 = moles x Mr = 0.1 x 2 = 0.2 gTask 1Use the “know / molar ratio / find” method to answer the following.Calculate the mass of Mg that is needed to produce 0.8 g of MgO.2 Mg + O2 2 MgOCalculate the mass of CaO that can be produced from 10 g of CaCO3.CaCO3 CaO + CO2Calculate the mass of O2 that is needed to react with 3.9 g of K.4 K + O2 2 K2OChallenge TaskCalculate the mass of Al that is needed to react with 1.92 g of O2.4 Al + 3 O2 2 Al2O3Homework 4A compound contained 6 g of magnesium and 4 g of oxygen. Calculate the simplest formula. (3)Ar(Mg) = 24Ar(O) = 16119 g of titanium chloride contained 48 g of titanium. Calculate the mass of chlorine in the titanium chloride. (1)Calculate the simplest formula for titanium chloride. (3)Ar(Ti) = 48Ar(Cl) = 35.5An oxide of sodium, which had a mass of 6.2 g, contained 4.6 g of sodium.Calculate the mass of oxygen in the oxide of sodium. (1)Calculate the simplest formula for this oxide of sodium. (3)Ar(Na) = 23Ar(O) = 16Calculate the mass of oxygen (in g) needed to react with 10 g of calcium. (3) 2 Ca + O2 2 CaOAr(Ca) = 40 Ar(O) = 16 ................
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