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CHEM 110Solution Stoichiometry WorksheetCh. 4 1. How many mL of 0.125 M CaBr 2 solution must be used to react completely with 50.0 mL of 0.115 M AgNO 3 ? Hint: write and balance the equation first! CaBr 2 (aq) + 2 AgNO 3 (aq) 2 AgBr (s) + Ca(NO 3 ) 2 (aq) 0.050 L 1 × 0.115 mol AgN O 3 L × 1 molCa Br 2 2 mol AgN O 3 × L 0.125 molCa Br 2 × 1000 mL 1 L = 23 mL Vol = 23 mL 2. What is the molarity of an aqueous solution of potassium hydroxide if 21.34 mL is exactly neutralized by 20.78 mL of 0.116 M HCl by the following reaction: KOH (aq) + HCl (aq) ? KCl (aq) + H 2 O (l) 0.02078 L 1 × 0.116 mol HCl L × 1 mol KOH 1 mol HCl × 1 0.02134 L = 0.113 mol KOH L Molarity = 0.113 M 3. How many grams of baking soda, NaHCO 3 , are needed to completely neutralize 145 mL of “battery acid” which is H 2 SO 4 , if the concentration of the acid is 0.0364 M? 2 NaHCO 3 (aq) + H 2 SO 4 (aq) Na 2 SO 4 (aq) + 2 H 2 O (l) + 2 CO 2 (g) 0.145 L 1 × 0.0364 mol H 2 SO 4 L × 2 mol NaHC O 3 1 mol H 2 SO 4 × 84 g 1 mol NaHC O 3 = 0.89 g Mass = 0.89 g