How many moles of water will be produced

How many moles of water will be produced when 8 grams of hydrogen gas react with the oxygen in the air? Episode 801

Stoichiometry • Study of the quantity (mass) relationships in a chemical reaction • Based on balanced equations 2 Mg + O 2 2 Mg. O • Two atoms of magnesium reaction with 1 oxygen molecule to form 2 magnesium oxide formula units or • Two moles of magnesium atoms react with 1 mole of oxygen molecules to form 2 moles of magnesium oxide formula units Episode 801

• The coefficients in a balance equation give the MOLE RATIO for the substances involved in the reaction. – Example problem: – When elemental aluminum reacts with elemental iodine, aluminum iodide is produced. 2 Al + 3 I 2 2 Al. I 3 • Mole ratios: ____Al: 2 2 ____Al: 3 2: ____I 3 2 2 ____Al. I 3 • If you start with 4 moles of Al, how many moles of Al. I 3 will be produced? ? mol Al. I 3 = 4 mol Al 2 mol Al. I 3 2 mol Al = 2 mol Al. I 3 Episode 801

Problem Set 1 2 N 2 H 4 + N 2 O 4 3 N 2 + 4 H 2 O BE SURE TO BALANCE THE EQUATION FIRST!! ? mol N 2 H 4 = 2. 72 mol N 2 H 4 1 mol N 2 O 4 2 mol N 2 H 4 = 1. 36 mol N 2 O 4 ? mol N 2 = 2. 72 mol N 2 H 4 3 mol N 2 2 mol N 2 H 4 = 4. 08 mol N 2 Episode 801

How many moles of water will be produced when 8 grams of hydrogen gas react with the oxygen in the air? 2 H 2 + O 2 2 H 2 O (Hint: We will need to change grams of H 2 to moles H 2) ? mol H 2 O = 8 g H 2 1 mol H 2 2 mol H 2 O 2 g H 2 2 mol H 2 = 4 mol H 2 O (Hint: To “make the switch” between different substances in a reaction, use the mole ratio from the balanced equation. ) Episode 801

Problem Set 2 In photosynthesis, carbon dioxide and water react to form glucose, C 6 H 12 O 6 and oxygen gas. 6 CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2 If 15. 6 g of carbon dioxide react, how many moles of glucose will be produced? ? mol C 6 H 12 O 6 = 15. 6 g CO 2 1 mol CO 2 44 g CO 2 1 mol C 6 H 12 O 6 6 mol CO 2 = 0. 059 mol C 6 H 12 O 6 How many grams of carbon dioxide must react to form 0. 25 moles of glucose? ? g CO 2 = 0. 25 mol C 6 H 12 O 6 6 mol CO 2 44 g CO 2 1 mol C 6 H 12 O 6 1 mol CO 2 = 66 g CO 2 Episode 801

Challenge Problem • When nitrogen and hydrogen react, they form ammonia gas, which has the formula NH 3. If 56. 0 g of nitrogen are used up in the reaction, how many grams of ammonia will be produced? Episode 801