Concepts
What is stoichiometry?
study of quantitative relationships between amounts of reactants used and products formed by a chemical reaction
Equation: N₂ + 3H₂ → 2NH₃
If you start with 4 moles of hydrogen gas (H₂), how many moles of ammonia (NH₃) will be produced?
2.67 moles NH3
Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂
If you have 2.0 moles of hydrochloric acid (HCl), how many grams of sodium chloride (NaCl) are produced?
116.88 g NaCl
Equation: N₂ + 3H₂ → 2NH₃
If you start with 28.0 grams of nitrogen gas (N₂), how many grams of ammonia (NH₃) can be produced?
34.06 g NH3
2H₂ + O₂ → 2H₂O
You have 4 moles of hydrogen gas (H₂) and 1 mole of oxygen gas (O₂).
Which reactant is limiting, and how many moles of water (H₂O) will be produced?
O2 is limiting and 2 mol H2O
True or false: the mass of the reactants should equal the mass of the products
True! Law of conservation of mass!
Equation: 2KClO₃ → 2KCl + 3O₂
If 6 moles of potassium chlorate (KClO₃) decompose, how many moles of oxygen gas (O₂) are formed?
9 moles O2
Aluminum reacts with oxygen gas to form aluminum oxide.
If 1.5 moles of aluminum (Al) react, how many grams of aluminum oxide are produced?
Equation: 2Al + 3Cl₂ → 2AlCl₃
If you react 10.8 grams of aluminum (Al), how many grams of aluminum chloride (AlCl₃) will be produced?
53.34 g AlCl3
Sodium reacts with chlorine gas to produce sodium chloride.
You have 3 moles of sodium and 1 mole of chlorine gas.
Which reactant is limiting, and how many moles of sodium chloride (NaCl) will be produced?
Cl2 is limiting, 2 mol NaCl
What is a mole ratio?
ratio between number of moles of any 2 substances in a chemical equation
Equation: 2Al + 3Br₂ → 2AlBr₃
If you have 5 moles of aluminum (Al), how many moles of aluminum bromide (AlBr₃) can be produced?
5 moles AlBr3
Zn + 2HCl → ZnCl₂ + H₂
If you start with 130 grams of zinc (Zn), how many moles of hydrogen gas (H₂) will be produced?
1.99 mol H2
Equation: CH₄ + 2O₂ → CO₂ + 2H₂O
If 16.0 grams of methane (CH₄) are burned, how many grams of carbon dioxide (CO₂) are produced?
44.01 g CO2
2Al + 3Cl₂ → 2AlCl₃
You have 10 grams of aluminum (Al) and 15 grams of chlorine gas (Cl₂).
Which reactant is limiting, and how many grams of aluminum chloride (AlCl₃) will be produced?
Cl2 limiting, 18.67 g AlCl3
Why are mole ratios important
They allow us to go from moles of one compound to another (show us their relationship through the reaction)
Hydrogen gas reacts with oxygen gas to produce water.
If you have 6 moles of oxygen gas (O₂), how many moles of water (H₂O) can be formed?
12 moles H2O
Calcium hydroxide reacts with sulfuric acid (H2SO4) to produce calcium sulfate and water.
If you start with 98.1 grams of calcium hydroxide, how many moles of water will be formed?
2.64 mol H2O
Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas.
If you start with 12.2 grams of magnesium (Mg), how many grams of magnesium chloride are produced?
47.80 g MgCl2
Nitrogen gas and hydrogen gas react to make ammonia.
You have 10 grams of nitrogen gas (N₂) and 15 grams of hydrogen gas (H₂).
Which reactant is limiting, and how many grams of ammonia (NH₃) will be produced?
N2 limiting, 12.16 g NH3
Change compound 1 grams to moles, then go from moles of compound 1 to compound 2 (mole ratio), then go from moles of compound 2 to grams of compound 2.
(grams to moles, moles to moles, moles to grams)
Aluminum reacts with hydrochloric acid to produce aluminum chloride and hydrogen gas.
If 4 moles of aluminum (Al) react, how many moles of hydrogen gas (H₂) will be produced?
6 moles H2
If you decompose 245 grams of potassium chlorate (KClO₃) into potassium chloride and oxygen gas, how many moles of oxygen gas are produced?
3.00 mol O2
Calcium hydroxide reacts with phosphoric acid (H₃PO₄) to form calcium phosphate and water.
If you start with 148.2 grams of calcium hydroxide how many grams of water (H₂O) are produced?
72.08 g H2O
2H₂ + O₂ → 2H₂O
You have 10 moles of hydrogen gas (H₂) and 4 moles of oxygen gas (O₂).
Which reactant is limiting, and how many moles of excess reactant are left?