Introduction to Stoichiometry How are mol to mol and gram to gram conversion calculated for different elements/compounds in a chemical rxn?

What is Stoichiometry? The quantitative relationships between amounts of reactants used and products formed by a chemical reaction. Shows how much reactant is needed to produce each product Coefficients are the number of each compound needed or produced in the rxn.

Just like a recipe…. 1 Banana + 5 Strawberries  2 Smoothies How many smoothies can be made from 2 bananas if you had plenty of strawberries? How many smoothies can be made from 25 strawberries if you had plenty of bananas? 4, ratio is 1:2 10, ratio is 5:2

Mole Ratios Ratios between: 2 Al + 3 Br2 → 2 AlBr3 Reactants, Products, or Reactants and Products 2 Al + 3 Br2 → 2 AlBr3 Because this shows the relationships in balanced equations, molar ratios are used as conversion factors! ONLY way to convert BETWEEN DIFFERENT elements/compounds in a chemical equation. Determine some mole ratios for this equation!

Aluminum chloride reacts with oxygen to form aluminum chlorate Ex: Write molar ratios for the following example: Aluminum chloride reacts with oxygen to form aluminum chlorate Write the molar ratios for the following substances: Aluminum chloride and oxygen Oxygen and aluminum chlorate Aluminum chloride and aluminum chlorate

On Your Own: Mole ratios 1. _____BaCl2 + _____KClO3 → _____Ba(ClO3)2 + _____KCl Moles BaCl2 : Moles KCl Moles KClO3 : Moles KCl 2. _____H2 + _____O2 → _____H2O Moles H2 : Moles H2O Moles O2 : Moles H2

Mole to Mole Conversions Use dimensional analysis to convert from one substance to another substance in a chemical reaction Helps to determine how much you need to start with or how much you would end up with

Mole to Mole Conversions #3 in your packet How many moles of CO2 are produced from the combustion of 7.3 moles C4H10? 2 C4H10(g) + 13 O2(g)  8 CO2(g) + 10 H2O(g) 7.3 mols C4H10 8 mols CO2 29.2 mols CO2 mols C4H10 2

Mole to Mole Conversions #4 in your packet How many moles of iron are produced when 1.75 moles of iron (III) sulfate reacts with zinc? Fe2(SO4)3(aq) + 3 Zn(s)  3 ZnSO4(aq) + 2 Fe(s) 1.75 mols Fe2(SO4)3 2 mols Fe 3.5 mols Fe = 1 mols Fe2(SO4)3

On Your Own: Mole to Mole Conversions 5. _____C3H8(g) + _____O2(g) → _____H2O(g) + _____CO2(g)   How many moles of water will be produced if 1.2 mol of oxygen reacts with excess C3H8? 6. ____K(s) + _____HgCl2(aq) → _____Hg(s) + _____KCl(aq) How many moles of potassium are needed to react with 0.633 moles of HgCl2? 0.96 mols H2O 1.27 mols K

Stoichiometry Conversions Use dimensional analysis to convert between grams, moles and particles of different substances in a chemical reaction! 1 mol = 6.02 x 1023 representative particles 1 mol = molar mass (g) Mole Ratios **1 mol = 22.4 L of gas @ STP Standard temperature and pressure: 1 atm & 0°C Liters = Volume of Gas

Molar Volume of A Gas Gases are measured in Liters not grams When converting with a gas at STP (standard temperature and pressure) use the conversion factor: 1 mol = 22.4 L Ex. 2 H2(g) + O2(g)  2 H2O(g) If you had 4.8 moles of hydrogen gas, what volume of water vapor would be produced? 4.8 mol H2 x 2 mol H2O x 22.4 L H2O = 107.52 = 110 L H2O 1 2 mol H2 1 mol H2O

Stoichiometry Conversions #7 in your packet How many grams of solution are produced when 25.03 grams of aqueous iron (III) sulfate are reacted with an excess of zinc metal? Fe2(SO4)3 (aq) + 3 Zn (s) → 3 ZnSO4 (aq) + 2 Fe (s) 25.03 g Fe2(SO4)3 mol Fe2(SO4)3 1 mol ZnSO4 3 161.46 g ZnSO4 30.3 g ZnSO4 399.91 mol Fe2(SO4)3 1 mol ZnSO4 1 g Fe2(SO4)3

Stoichiometry Conversions #8 in your packet How many grams of metal are produced when 100.0 grams of aqueous iron (III) nitrate reacts with an excess amount of calcium? 2 Fe(NO3)3 (aq) + 3 Ca (s) → 2 Fe (s) + 3 Ca(NO3)2 (aq) 100.0 g Fe(NO3)3 mol Fe(NO3)3 1 2 mol Fe 55.85 g Fe 23.1 g Fe 241.88 mol Fe(NO3)3 2 1 mol Fe g Fe(NO3)3

On Your Own - Stoichiometry Conversions 9. How many grams of barium chloride solution would be needed to produce 33 grams of iron (III) chloride when reacted with iron (III) sulfate ? 3 BaCl2 (aq) + Fe2(SO4)3 (aq) → 2 FeCl3 (aq) + 3 BaSO4 (s) 33 g FeCl3 g FeCl3 162.2 mol FeCl3 1 63.5 g BaCl2 2 mol BaCl2 3 g BaCl2 208.23 1

Stoichiometry Conversions #10 in your packet a. Hydrogen gas reacts with fluorine gas. How many grams of gas will form from 1.7 mole of hydrogen gas with sufficient fluorine? H2 (g) + F2 (g) → 2 HF (g) 1.7 moles H2 2 mol HF 20.01 g HF 68.0 g HF 1 1 mol HF Mole H2

Stoichiometry Conversions #10 in your packet b. Hydrogen gas reacts with fluorine gas. How many moles of fluorine are needed to produce 160 grams of gas? H2 (g) + F2 (g) → 2 HF (g) 160 grams HF 1 mol HF 1 mol F2 4.00 mol F2 20.01 2 mol HF g HF

On Your Own - #11 in packet 5 mol NH3 336 L H2 a) If 2.5 moles of N2 react, how many moles of NH3 can be produced? b) If 10.0 moles of NH3 are produced, how many liters of H2 would be needed? c) If 3.50 grams of H2 react, how many molecules of NH3 would be made? d) If 0.60 grams of NH3 are produced, how many grams of N2 are required? 5 mol NH3 336 L H2 6.96 x 1023 molecules NH3 0.493 g N2