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 802 N 2 (g) + 3H 2 (g)  2NH 3 (g) ? g NH 3 = 56.0 g N 2 28g N 2 1 mol N 2 1 mol NH 3 2 mol NH 3 17g NH 3 = 68g NH 3

Sodium metal reacts with oxygen to produce solid sodium oxide. How many grams of sodium must react to produce 42.0 grams of sodium oxide? When 12.0 grams of hydrogen reacts with oxygen, how many grams of water are produced? 4Na (s) + O 2 (g)  2Na 2 O (s) 2H 2 (g) + O 2 (g)  2H 2 O (l) ? g Na = 42.0g Na 2 O 62g Na 2 O 1 mol Na 2 O 2 mol Na 2 O 4 mol Na 1 mol Na 23g Na = 31g Na ? g H 2 O = 12.0g H 2 2g H 2 1 mol H 2 2 mol H 2 2 mol H 2 O 1 mol H 2 O 18g H 2 O = 108g H 2 O Episode 802

Actual Yield – Amount of product produced when the reaction is performed in a lab Theoretical Yield – Amount of product expected to be produced based on the balanced equation and the amount of reactants – Calculated using stoichiometry Percent Yield – (actual yield/theoretical yield) x 100% Episode 802

Percent Yield in Lab Actual yield of CO 2 = 0.13g – (from lab data) Calculated theoretical yield from the balanced equation: NaHCO 3 + HCl  NaCl + CO 2 + H 2 O ? g CO 2 = 0.23g NaCO 3 84g NaCO 3 1mol NaCO 3 1mol CO 2 44g CO 2 = 0.12g CO 2 % yield = 0.13g 0.12g x 100 = 108% Episode 802

What is the % yield of carbon dioxide when 5.99 grams of propane are burned and grams of carbon dioxide are collected? C 3 H 8 + 5O 2  3CO 2 + 4H 2 O ? g CO 2 = 5.99g C 3 H 8 44g C 3 H 8 1 mol C 3 H 8 3 mol CO 2 1 mol CO 2 44g CO 2 = 17.97g CO 2 % yield = g 17.97g x 100 = 67% Episode 802