Sample Quiz/Exam Questions (for Exam Builder)
1. Calculate the mass of phosphine, PH3, that can be prepared when 10.0 g of calcium phosphide reacts with water:
Ca3P2(s) + H2O(l) ->Ca(OH)2(aq) + PH3(g)
2. Iron metal can react with O2 (in two different ways) to produce two different oxides, Fe2O3(s) or Fe3O4(s).
(a) Write balanced chemical equations to describe each reaction.
(b) If 167.6 g of Fe reacts completely with excess O2(g) to produce 231.6 g of product, which oxide was formed?
3. How many milliliters of 0.125 M HNO3 are required to react completely with 1.30 g of Sr(OH)2?
HNO3(aq) + Sr(OH)2(aq) ® Sr(NO3)2 + H2O(l)
4. Calcium hypochlorite (Ca(OCl)2) is used as a bleaching agent. Treating a mixed solution of sodium hydroxide and calcium hydroxide with gaseous chlorine by the following unbalanced equation produces it:
NaOH(aq) + Ca(OH)2(s) + Cl2(g) ® Ca(OCl)2(aq) + NaCl(aq) + H2O(l)
a) How many grams of calcium hypochlorite can be produced from 10.0 g of NaOH, 10.0 g of Ca(OH)2 and excess chlorine gas?
b) If only 15.2 g of Ca(OCl)2 were actually recovered, what is the percent yield of this reaction?
5. Given 6 mol of each reactant, which one would be limiting in the following unbalanced reaction?
Au + NaCN + O2 + H2O → NaAu(CN)2 + NaOH
a) Au
b) NaCN
c) O2
d) H2O
e) There is no limiting reactant.