Drill: Calculate the % composition of each element in Fe 2 (SO 4 ) 3

Molar Conversions

Moles The standard unit of measure for the amount of a substance in numbers

Dozen = 12 of anything

Moles = the amount of a substance that would = its mass in g from the PT

Moles = x of anything

Molar Conversions Mass to moles Volume of a gas to moles Particles to moles Volume of a solution to moles

Moles First

Mass to Moles Use atomic masses from the periodic table NaCl = 58.5 g/mole

Gas Volume to Moles At STP: 22.4 L/mole Non-STP: PV = nRT PV RT n =

Particles to Moles Use Avogadro’s Number 6.02 x atoms, molecules, etc/mole

Soln Volume to Moles Multiply molarity times volume n = M x V

Solution Measures Molarity (M) = the number of moles of solute per liter of solution Others later

Convert 7.0 g of silicon to moles

Convert 250 g of CaCO 3 to moles

Convert 3.0 moles of helium to grams

Convert 11.2 L of oxygen gas at STP to moles

Convert 0.20 moles of helium to volume at STP

Convert: 2.0 x atoms He to moles

Convert 3.0 moles of glucose to molecules

Convert 250 mL of 0.10 M HCl to moles

Drill: Determine the volume required to make 60.0 g NaOH into a 0.75 M solution

Convert 6.8 g NH 3 to volume of gas at STP

Convert 3.0 x molecules of CO 2 to mass in kg

Drill: Calculate the number molecules in 32  g of Fe 2 O 3

First Test Next Thursday on nomenclature, molar conversions, & reactions.

Calculate the number of atoms in 16 ng of Fe 2 (SO 4 ) 3

Empirical Formula

Lowest whole number ratio of elements in a compound C 6 H 12 O 6 : EF = CH 2 O

Determining Empirical formulas from percent composition

Assume 100 g Change % directly to grams Use molar conversions to convert grams to moles Divide each molar amount by the smallest molar amount

Find empirical for a compound with: 70.0 % Fe 30.0 % O

Find empirical for a compound with: 40 % Ca 12 % C 48 % O

Find empirical for a compound with: 40.0 % C 6.7 % H 53.3 % O

Molecular Formula

The actual whole number for each element in the compound

Molecular Formula C 6 H 12 O 6 Empirical Formula CH 2 O

Solving MF from EF 1) Solve empirical mass 2) Divide EM into MM 3) Multiply EF by quotient

Drill: Calculate the mass of solute required to make 40.0 mL of 0.25 M Pb(NO 3 ) 2

Test Review on Nomenclature, Molar conversions, & % Composition.

Calculate the % composition of each element in Pb(NO 3 ) 2

Calculate the empirical formula of a substance containing 62.7 % Po, 28.8 % O, & 8.4 % N.

Calculate the molecular formula of a substance with an empirical formula of NH 2 & a molecular mass of 32 g/mole.

Name each of the following: SeOMgS PbO 2 Cl 2 O KNO 3 ScCl 3

Derive formulas for each: Cesium oxide Barium chloride Calcium phosphate Manganese(II) chlorate

Name each of the following: NH 4 ClBaSO 4 KC 2 H 3 O 2 K 2 HPO 3 KNO 3 CuBrO Li 2 CO 3 MgC 2 O 4

Name each of the following: HClH 2 SO 4 H 2 S H 3 PO 3 HNO 3 HBrO H 2 CO 3 HBrO 4

Calculate the number of hydrogen atoms in 1.8 kg of PH 5.

Calculate the volume at STP of 6.0 ng of NO.

Calculate the mass of KBr required to make 250 mL of a 0.40 M solution.

Chapter 3 General Define all the Key Terms on page 74

Atomic Mass Work problems: on page 75

Avogadro’s Num. Work problems: on page 75

Molar Conversions Work problems: on page 75 & 76

% Composition Work problems: on page 76

Empirical Formula Work problems: on page 76 & 77

Balancing Rxns Work problems: 49 & 54 on page 77

Stoichiometry Work problems: 55 & 64 on page 77 & 78

Limiting Reactant Work problems: 65 & 74 on page 78 & 79