H3PO3(aq) + 3HI(aq)
1) A known amount of phosphorous triiodide is reacted with excess water and it is determined that the percent yield of phosphoric acid is less than 100%. Which of the following statements could explain why?
PI3(s) + 3H2O(l)
H3PO3(aq) + 3HI(aq)
(a) A side reaction formed products other than phosphoric acid.
(b) The phosphorous triiodide had some impurities in it.
(c) The phosphoric acid had some impurities in it.
(d) Too much water was added to the reaction.
(e) Too much phosphorous triiodide was added to the reaction.
2) A known amount of silver is reacted with excess sulfur and it is determined that the percent yield of silver sulfide is more than 100%. Which of the following statements could explain why?
2Ag(s) + S(s)
Ag2S(s)
(a) Some of the silver was spilled while being transferred to the reaction vessel.
(b) The product was not properly purified.
(c) A side reaction formed products other than silver sulfide.
(d) The silver had some impurities in it.
(e) The silver was massed incorrectly so that more silver was reacted than what was thought.
3) A known amount of vanadium(III) oxide is reacted with excess hydrogen and it is determined that the percent yield of vanadium(II) oxide is less than 100%. Which of the following statements could explain why?
V2O3(s) + H2(g)
2VO(s) + H2O(l)
(a) The vanadium(II) oxide had some impurities in it.
(b) Some of the product was lost in the purification process.
(c) The product was wet when it was massed.
(d) The vanadium(III) oxide was massed incorrectly so that less vanadium(III) oxide was reacted than what was thought.
(e) Too much hydrogen gas was added.
4) A known amount of sulfur is reacted with excess oxygen and it is determined that the percent yield of sulfur dioxide is less than 100%. Which of the following statements could explain why?
S(s) + O2(g)
SO2(g)
(a) The sulfur dioxide had some impurities in it.
(b) The sulfur had some impurities in it.
(c) Some of the sulfur dioxide gas leaked out of the collection system.
(d) The sulfur was massed incorrectly so that more sulfur was reacted than what was thought.
(e) A side reaction formed products other than sulfur dioxide.
5) A known amount of vanadium(III) oxide is reacted with excess hydrogen and it is determined that the percent yield of vanadium(II) oxide is more than 100%. Which of the following statements could explain why?
V2O3(s) + H2(g)
2VO(s) + H2O(l)
(a) The vanadium(II) oxide product was wet when it was massed.
(b) The vanadium(III) oxide had some impurities in it.
(c) A side reaction formed products other than vanadium(II) oxide and water.
(d) The vanadium oxide(III) was massed incorrectly so that more vanadium(III) oxide was reacted than what was thought.
(e) Too much hydrogen gas was added.
6) A known amount of iron is reacted with excess oxygen and it is determined that the percent yield of ferric oxide is less than 100%. Which of the following statements could explain why?
4Fe(s) + 3O2(g)
2Fe2O3(s)
(a) A side reaction formed products other than ferric oxide.
(b) The iron(III) oxide had some impurities in it.
(c) Too much oxygen was added to the reaction.
(d) Some of the iron was spilled while being transferred to the reaction vessel.
(e) The iron was massed incorrectly so that more iron was reacted than was thought.
7) A known amount of zinc sulfide is reacted with excess oxygen and it is determined that the percent yield of zinc oxide is less than 100%. Which of the following statements could explain why?
2ZnS + O2(g)
2ZnO(s) + 2S(s)
(a) Some of the sulfur product was mixed in with the zinc oxide.
(b) Some of the product was lost in the purification process.
(c) The zinc sulfide was massed incorrectly so that more zinc oxide was reacted than what was thought.
(d) Some of the zinc sulfide was spilled while being transferred to the reaction vessel.
(e) A side reaction formed products other than zinc oxide and sulfur.
8) A known amount of potassium iodide is reacted with excess chlorine and it is determined that the percent yield of potassium chloride is more than 100%. Which of the following statements could explain why?
2KI(s) + Cl2(g)
2KCl(s) + I2(s)
(a) A side reaction formed products other than potassium chloride and iodine.
(b) Some iodine was mixed in with the potassium chloride product.
(c) Some of the potassium chloride was lost in the purification process.
(d) The potassium iodide was massed incorrectly so that more potassium iodide was reacted than what was thought.
(e) Some of the potassium iodide was spilled while being transferred to the reaction vessel.
9) A known amount of phosphine is reacted with excess oxygen and it is determined that the percent yield of phosphorous pentoxide is more than 100%. Which of the following statements could explain why?
4PH3(g) + 8O2(g)
P4O10(g) + 6H2O(l)
(a) The product was wet when it was massed.
(b) The product was not purified correctly.
(c) The phosphine gas had some impurities in it.
(d) Some of the phosphine gas leaked out of the reaction vessel during the reaction.
(e) The phosphine was massed incorrectly so that more phosphine was reacted than what was thought.
10) A known amount of methane is reacted with excess oxygen and it is determined that the percent yield of carbon dioxide is more than 100%. Which of the following statements could explain why?
CH4(g) + 2O2(g)
CO2(g) + 2H2O(l)
(a) Too much oxygen gas was added.
(b) The carbon dioxide product was contaminated with oxygen gas.
(c) The methane had some impurities in it.
(d) Some product was lost in the purification process.
(e) The methane was massed incorrectly so that more methane was reacted than what was thought.