Stoichiometry Involving Solutions Worksheet Answers 1. Calculate the number of mL of 2.00 M HNO3 solution required to react with 216 grams of Ag according to the equation. 3 Ag(s) + 4 HNO3(aq) ---------> 3 AgNO3(aq) + NO(g) + 2 H2O(l) Set up Stoichiometry Table grams MM moles Ag 216 108 2 HNO3 2.7 M = moles/L so 2.0 = 2.7/x, x =1.35L or 1350 mL 2. Calculate in mL the volume of 0.500 M NaOH required to react with 3.0 grams of acetic acid. The equation is: NaOH(aq) + HC2H3O2(aq) -------> NaC2H3O2(aq) + H2O(l) Set up Stoichiometry Table NaOH HC2H3O2 grams 3g MM 60g/mol moles 0.05 moles 0.05 moles M = moles / L, so 0.5 = 0.05 / x, x = 0.1L or 100 ml. 3. Calculate the number of grams of AgCl formed when 0.200 L of 0.200 M AgNO3 reacts with an excess of CaCl2. The equation is: 2 AgNO3(aq) + CaCl2(aq) -------> 2 AgCl(s) + Ca(NO3)2(aq) Calculate moles of AgNO3 used M = mol/L, 0.2 = x / 0.2L, x = 0.04 moles Use the stoichiomety table AgNO3 Grams MM Moles 0.04 moles 5.74 g of AgCl can be produced CaCl2 AgCl 5.74g 143.4g/mol 0.04 moles Ca(NO3)2 4. Calculate the mass of AgCl formed when an excess of 0.100 M solution of NaCl is added to 0.100 L of 0.200 M AgNO3. Calculate the moles AgNO3 used. M = mol/L, 0.2 = x / 0.1L, x = 0.02 moles AgNO3 Grams MM Moles 2.89g of AgCl. CaCl2 0.02 moles AgCl 2.89g 143.4g/mol 0.02 moles Ca(NO3)2 5. Calculate: a) the mass of BaSO4 formed when excess 0.200 M Na2SO4 solution is added to 0.500 L of 0.500 M BaCl2 solution, and Write the balanced equation Na2SO4 + BaCl2 2NaCl + BaSO4 Calculate the moles of BaCl2. M = mol/L, 0.5 = x / 0.5L, x = 0.25 mol Set up stoichiometry table. Na2SO4 BaCl2 Grams MM Moles 0.25 moles 58.4g of BaSO4 should be produced NaCl BaSO4 58.4g 233.4 g/mol 0.25 moles b) the minimum volume of the Na2SO4 solution needed to precipitate the Ba2+ ions from the BaCl2 solution. Na2SO4 BaCl2 NaCl BaSO4 Grams 35.5g 58.4g MM 142.1 g/mol 233.4 g/mol Moles 0.25 moles 0.25 moles 0.25 moles Since it is a 1:1 ratio 0.25 moles of Na2SO4 are needed use the Molarity formula to determine the # of Liters needed. M = mol/L, 0.2 = 0.25/x, x = 1.25 L or 1250 mL. There would be 35.5 g of Na2SO4 in the 1250 ml. 6. A sample of impure sodium chloride weighing 1.00 grams is dissolved in water and completely reacted with silver nitrate solution. The dried precipitate of AgCl has a mass of 1.48 grams . Calculate the percentage of NaCl in the original impure sample. NaCl 0.585g 58.5 g/mol 0.010 moles Grams MM Moles AgNO3 AgCl 1.48 g 143.4 g/mol 0.010 moles NaNO3 There were 0.585 g of NaCl in the 1 g sample so the % NaCl is 58.5% 7. To neutralize the acid in 10.0 mL of 18.0 M H2SO4 that was accidentally spilled on a laboratory bench top, solid sodium bicarbonate was used. The container of sodium bicarbonate was known to weigh 155.0 g before this use and out of curiosity its mass was measured as 144.5 g afterwards. The reaction that neutralizes sulphuric acid this way is as follows. H2SO4 + 2 NaHCO3 --------> Na2SO4 + 2 CO2 + 2 H2O Calculate the amount of NaHCO3 used Mass of container before = 155.0 g Mass of container after = 144.5 g Mass of NaHCO3 = 10.5g Was sufficient sodium bicarbonate used? Calculate the limiting reactant and the maximum yield in grams of sodium sulphate. H2SO4 grams MM moles Moles neutralized NaHCO3 10.5g 84.0g/mol 0.125 mol Na2SO4 CO2 H2O 0.0625 moles Based on stoichiometry we can neutralize 0.0625 moles of H2SO4, use the molarity formula to see how many moles of H2SO4 were present. M = mol/L, 18 = mol / 0.010L, mol = 0.18 so since 0.18mol > 0.0625 moles we did not neutralize all the acid. 8. Barium nitrate and potassium sulphate solutions react and form a precipitate. What is the precipitate? How many mL of 0.40 M Ba(NO3)2 solution are required to precipitate completely the sulphate ions in 25 mL of 0.80 M K2SO4 solution? Write the balanced reaction Ba(NO3)2 + K2SO4 2KNO3 + BaSO4. Using solubility rules BaSO4 is the precipitate. Calculate moles of K2SO4 present M = mol/L, 0.8 = mol / 0.025L, mol = 0.02 mol. Since the K2SO4 and Ba(NO3)2 are in a 1:1 ratio the moles needed of Ba(NO3)2 is 0.02 moles. Use the molarity formula to calculate the volume of Ba(NO3)2 needed. M = mol/L, 0.4 = 0.02 mol / L, L = 0.05L or 0 mL. 9. What mass of silver chloride can be precipitated from a silver nitrate solution by 200 mL of a solution of 0.50 M CaCl2? Calculate moles of CaCl2 used M = mol/L, 0.5 = mol/0.2L, mol = 0.01 Write the balanced equation CaCl2 + 2AgNO3 Ca(NO3)2 + 2AgCl Use Stoichiometry to solve the problem CaCl2 grams MM moles 0.01 moles 2.87g of AgCl can be produced. AgNO3 Ca(NO3)2 AgCl 2.87 g 143.4 g/mol 0.02 moles
© Copyright 2025 Paperzz