contain the anion, or conjugate base, of the acid.65 . B
If the temperature of an exothermic reaction is increased, the reaction shifts to the left. If the
temperature of an endothermic reaction is increased, it shifts to the right. The reaction in
question has a negative enthalpy of reaction, meaning that it is an exothermic reaction. If the
temperature of this reaction is increased, the reaction will shift to the left.
66 . E
Boyle’s law states that at constant temperatures the volume of a gas is inversely proportional
to its pressure. Statement II is therefore correct. Statement III is also correct as density,
defined as mass divided by volume, will increase proportionally to pressure since the volume is
decreasing.
67 . A
Molality equals the number of moles of solute/kg of solvent. 200 g/[24 g/mol Mg + 71 g/mol for
2 Cl] is the number of moles of solute. This is also the value of molality since it is added to 1 kg
of solvent.
68 . C
Therefore, oxygen is the limiting reagent since it is the compound in the least amount.
According to the balanced equation, for every mole of oxygen you will get two moles of water.
Therefore, to discover how many moles of water would be produced, multiply the number of
moles of oxygen you begin with by two, to account for the fact that two moles of water are
produced for every mole of oxygen. Thus, the correct equation would be (2 mol H 2 O 2 /1 mol of
O 2 )(100/32 mol of O 2 ).69 . D
Perhaps the easiest way to solve such a problem is to imagine a particular sample mass of the
compound. For the sake of convenience, choose 100 grams, though any mass will let you
arrive at the correct answer. Because the oxide of arsenic contains only arsenic and oxygen, a
100-gram sample would contain 65.2 grams of arsenic and the remainder, 34.8 grams, must be