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 2Mg + O2  2MgO 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 I2  2 AlI3 Mole ratios: ____Al: ____I2 ____Al: ____AlI3 ____I2: ____AlI3 If you start with 4 moles of Al, how many moles of AlI3 will be produced? 2 3 2 2 3 2 ? mol AlI3 = 4 mol Al 2 mol AlI3 = 2 mol AlI3 2 mol Al Episode 801

BE SURE TO BALANCE THE EQUATION FIRST!! Problem Set 1 N2H4 + N2O4  N2 + H2O BE SURE TO BALANCE THE EQUATION FIRST!! ? mol N2H4 = 2.72 mol N2H4 ? mol N2 = 2.72 mol N2H4 2 3 4 2.72 mol N2H4 1 mol N2O4 = 1.36 mol N2O4 2 mol N2H4 2.72 mol N2H4 3 mol N2 = 4.08 mol N2 2 mol N2H4 Episode 801

(Hint: We will need to change grams of H2 to moles H2) How many moles of water will be produced when 8 grams of hydrogen gas react with the oxygen in the air? 2 H2 + O2  2 H2O (Hint: We will need to change grams of H2 to moles H2) ? mol H2O = 8 g H2 1 mol H2 2 mol H2O = 4 mol H2O 2 g H2 2 mol H2 (Hint: To “make the switch” between different substances in a reaction, use the mole ratio from the balanced equation.) Episode 801

Problem Set 2 6 CO2 + 6 H2O  C6H12O6 + 6 O2 In photosynthesis, carbon dioxide and water react to form glucose, C6H12O6 and oxygen gas. 6 CO2 + 6 H2O  C6H12O6 + 6 O2 If 15.6g of carbon dioxide react, how many moles of glucose will be produced? ? mol C6H12O6 = 15.6g CO2 1 mol CO2 1 mol C6H12O6 = 0.059 mol C6H12O6 44g CO2 6 mol CO2 How many grams of carbon dioxide must react to form 0.25 moles of glucose? ? g CO2 = 0.25 mol C6H12O6 6 mol CO2 44g CO2 = 66g CO2 1 mol C6H12O6 1 mol CO2 Episode 801

Challenge Problem When nitrogen and hydrogen react, they form ammonia gas, which has the formula NH3. If 56.0 g of nitrogen are used up in the reaction, how many grams of ammonia will be produced? Episode 801