Gravimetric Analysis Review Questions Problems 4.77 If 30.0 mL of 0.150 CaCl2 is added to 15.0 mL of 0.100 M M AgNO3, what is the mass in grams of AgCl precipitate? 4.78 A sample of 0.6760 g of an unknown compound containing barium ions (Ba2+) is dissolved in water and treated with an excess of Na2SO4. If the mass of the BaSO4 precipitate formed is 0.4105 g, what is the percent by mass of Ba in the original unknown compound? 4.79 How many grams of NaCl are required to precipitate most of the Ag ions from 2.50 X 102 mL of 0.0113 AgNO3 solution? Write the M net ionic equation for the reaction. 4.80 The concentration of Cu2+ ions in the water (which also contains sulfate ions) discharged from a certain industrial plant is determined by adding excess sodium sulfide (Na2S) solution to 0.800 L of the water. The molecular equation is: Na2S(aq) + CuSO4(aq) Na2SO4(aq) + CuS(s) → Write the net ionic equation and calculate the molar concentration of Cu2+ in the water sample if 0.0177 g of solid CuS is formed.
Gravimetric Analysis Review Questions Problems 4.77 If 30.0 mL of 0.150 M CaCl2 is added to 15.0 mL of 0.100 M AgNO3, what is the mass in grams of AgCl precipitate? 4.78 A sample of 0.6760 g of an unknown compound containing barium ions (Ba2+) is dissolved in water and treated with an excess of Na2SO4. If the mass of the BaSO4 precipitate formed is 0.4105 g, what is the percent by mass of Ba in the original unknown compound? 4.79 How many grams of NaCl are required to precipitate most of the Ag ions from 2.50 X 102 mL of 0.0113 M AgNO3 solution? Write the net ionic equation for the reaction. 4.80 The concentration of Cu2+ ions in the water (which also contains sulfate ions) discharged from a certain industrial plant is determined by adding excess sodium sulfide (Na2S) solution to 0.800 L of the water. The molecular equation is: Na2S(aq) + CuSO4(aq) → Na2SO4(aq) + CuS(s) Write the net ionic equation and calculate the molar concentration of Cu2+ in the water sample if 0.0177 g of solid CuS is formed.
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