NOTE – YOU WILL NEED A SCIENTIFIC CALCULATOR FOR …



Ch 11 The MoleNOTE – YOU WILL NEED A SCIENTIFIC CALCULATOR FOR THIS CHAPTER!11.1 Measuring matterHow do we measure items?You can measure ____________ ,________________,or ________________,You can count ________________.We measure mass in________________.We measure distance in _________________.We measure volume in________________.We count pieces in _________________. Counting ParticlesChemists need a convenient method for accurately counting the number of atoms, molecules, or formula units of a substance.The _____________is the SI base unit used to measure the amount of a substance.Moles (is abbreviated: mol)It is an __________________, defined as the number of carbon atoms in exactly 12 grams of carbon-12.1 mole = _______________________ of the representative particles.Treat it like a very large dozen!6.022 x 1023 is called ________________________________________.Similar Words for an amountPair: 1 pair of shoelaces = ____ shoelacesDozen: 1 dozen oranges = ____ orangesCase: 1 case of Dr. Pepper = ____ cans Dr. PepperGross: 1 gross of pencils = ______ pencilsReam: 1 ream of paper = _______sheets of paperWhat are Representative Particles?The___________________ pieces of a substance:For a molecular compound: it is the_____________________.For an ionic compound: it is the formula_____________ (made of ions).For an element: it is the __________.Remember the 7 diatomic elements? (made of molecules)Types of questions How many oxygen atoms in the following?CaCO3Al2(SO4)3 How many ions in the following?CaCl2NaOHAl2(SO4)3Converting Between Moles and Particles____________________________________ must be used.Moles to particlesExample:Find the number of molecules in 3.50 mol of sucrose.Always start with what you are given!Particles to molesUse the inverse of Avogadro’s number as the conversion factor.Example:Find the number of moles in 2.11 x 1024 molecules of sucrose.Practice problems (round to 3 sig. figs.)How many molecules of CO2 are in 4.56 moles of CO2?How many moles of water is 5.87 x 1022 molecules?How many atoms of carbon are in 1.23 moles of C6H12O6?How many moles is 7.78 x 1024 formula units of MgCl2?11.2 Mass and the MoleThe Mass of a Mole1 mol of copper and 1 mol of carbon have _______________________________.One copper atom has a different mass than 1 carbon atom.Remember relative atomic mass?The ___________was one twelfth the mass of a carbon-12 atom.Since the mole is the number of atoms in 12 grams of carbon-12,the _______________________________________________________is also the mass of _______________ of those atoms in grams.__________________ (MM) is the ______________________________________ of any pure substance.Also called _________________________ (FW)6556081311800Equals the_____________ of 1 mole of an element in grams (from periodic table)12.011 grams of C has the same _______________________________ as ___________ grams of H ___________ grams of iron.We can write this as: ____________________________We can count things by weighing them.Using Molar MassMoles to mass4660902349500Convert mass to moles with the inverse molar mass conversion factor.41359951674850021562514521100ExamplesHow much would 2.34 moles of carbon weigh?How many moles of magnesium is 24.31 g of Mg?How many atoms of lithium is 1.00 g of Li?How much would 3.45 x 1022 atoms of U weigh?Using Molar Mass (cont.)This figure shows the steps to complete conversions between mass and atoms.419100457200011.3 Moles of compoundsChemical Formulas and the MoleChemical formulas indicate the numbers and types of atoms contained in one unit of the compound.201676020193000One mole of CCl2F2 contains _______________ of C atoms, __________________ of Cl atoms, and two moles of F atoms.The Molar Mass of CompoundsThe molar mass of a compound equals the molar mass of each element, multiplied by the moles of that element in the chemical formula, added together.The molar mass of a compound demonstrates the law of conservation of mass.in 1 mole of H2O molecules there are ________moles of H atoms and_______ mole of O atoms (think of a compound as a molar ratio)To find the mass of one mole of a compound _____________________ the number of__________ of the elements present__________________ the number times their ____________ (from the periodic table)______________them up for the total massCalculating Molar Mass Example20764502965450011239502679700015176528448000Calculate the molar mass of magnesium carbonate, MgCO3.More Examples – Molar mass of compoundsCalculate the molar mass of the following and tell what type of substance it is: Na2S N2O4 C Ca(NO3)2 C6H12O6 (NH4)3PO4Moles to Mass Conversion for CompoundsFor elements, the conversion factor is the molar mass of the elements.The procedure is the same for compounds, except that you must ___________________________________________________ of the compound.Mass to Moles Conversion for CompoundsThe conversion factor is the inverse of the molar mass of the compound.12296246771700For exampleHow many moles is 5.69 g of NaOH?Mass to Particles Conversion for CompoundsConvert mass to moles of compound with the inverse of molar mass.Convert moles to particles with Avogadro’s number.This figure summarizes the conversions between mass, moles, and particles.1039950425450011.4 Empirical and Molecular formulasPercent CompositionThe ________________________________ of any element in a compound can be found by dividing the mass of the element by the mass of the compound and multiplying by 100.42799013462000The percent by mass of each element in a compound is the _____________________________ of a compound.Percent composition of a compound can also be determined from its chemical formula.4381508382000Like all percent problems: Find the mass of each of the _____________________.Next, ___________________________________of the compound; then x ___________ExampleCalculate the percent composition of a compound that is made of 29.0 grams of Ag with 4.30 grams of S(Assume you have one mol of substance)More ExamplesCalculate the percent composition of C2H4?How about Aluminum carbonate?Empirical FormulaThe ___________________________ for a compound is the _______________________________________ of the elements.To calculate the empirical formula from percent by mass:1) Assume you have 100.00 g of the compound. 2) Convert the mass of each element to moles.3) Find the simplest mole ratio for element.Example) Finding an Empirical FormulaA blue solid is found to contain 36.84% nitrogen and 63.16% oxygen. What is the empirical formula for this unknown solid?Step 1- Find the number of moles in a 100 g sample.Step 2 – Find the mole ratio by dividing every number of moles by the smallest number of moles.***Multiply to get a whole number ratio.Step 3 – Use the simplest ratio to write the empirical formula.Empircal vs MolecularThe empirical formula may or may not be the same as the molecular formula.Molecular formula of hydrogen peroxide = H2O2Empirical formula of hydrogen peroxide = HOMolecular FormulaThe ________________________________ specifies the _______________________________ of each element in one molecule or formula unit of the substance.Molecular formula is always a _________________________________ of the empirical formula.To find the molecular formula the molar mass of the compound must be determined through experimentation and compared with the mass represented by the empirical formula.1790065243205 For example) Further testing on the previous compound found that the molar mass of the compound is 152.022 g/mol.A molecular formula can be represented as the empirical formula multiplied by an integer n.Continuing with our previous compound n = 2, so the molecular formula is _________. 11.5 Formulas of hydratesNaming Hydrates3371850317500A __________________ is a compound that has a specific number of water molecules bound to its atoms.The number of water molecules associated with each formula unit of the compoundis written following a dot.ExampleAnalyzing HydratesWhen heated, water molecules are released from a hydrate leaving an ______________________________________.To determine ________________________________, find the number of moles of water associated with 1 mole of hydrate.______________hydrate._____________ to drive off the water.Weigh the anhydrous compound._____________ and convert the difference to moles.The _____________________________________ to moles of anhydrous compound is the ____________________________________ in the hydrate.Use of HydratesAnhydrous forms of hydrates are often used to __________________________, particularly during shipment of electronic and optical equipment.In chemistry labs, anhydrous forms of hydrates are used to remove moisture from the air and keep other substances dry. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download