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# The enthalpy change of solution formation for KBr in water is \+19.8 kJ/mol. However, the solubility of KBr is very high in water. This is due to:
## dipole-dipole attractions.
## a higher entropy (disorder) in solution compared to the solid. 
## an exothermic solvation process. 
## solvent-solvent interactions. 
## an endothermic solvation process. 
# Which of the following is/are immiscible in water?
## CCl4(carbon tetrachloride)
## CH3OH (methanol)
## C6H6(benzene)
## both a and c
## all three
# Which of the following solutes will produce the largest *total molality of solute particles* when dissolved in water?a) 2 moles of NaCl
## 1 mole of ethanol
## 1 mole of Mg(Cl)2
## 2 moles of methanol
# A 5.50 g sample of a compound is dissolved in 250 grams of benzene solvent. The freezing point of this solution is 1.02° C below that of pure benzene. What is the molar mass of this compound? (K{~}f~ for benzene = 5.12° C/molal)
## 22.0
## 110
## 220
## 44.0
# Calculate the molality of ethanol (CH{~}3{~}CH{~}2{~}OH) in a water solution which is prepared by mixing 39.5 grams of ethanol with 100.0 g of H{~}2{~}O at 20° C.
## 0.086 m
## 0.094 m
## 1.24 m
## 8.59 m
# A 20.0 gram sample of methanol (CH{~}3{~}OH) was dissolved in 30.0 grams of water. The mole fraction of methanol is:
## 0.400
## 0.625
## 0.728
## 0.273
# If the vapor pressure of water at 90° C is 0.692 atm, then what is the vapor pressure of a solution (in atm) made by dissoving 1.00 mole of urea in 1.00 kg of water?
## 0.692
## 0.680
## 0.668
## 0.656
# The colligative property of boiling point elevation is due to:a) osmosis of solute particles.
## lowered vapor pressure of solution relative to pure solvent.
## ion-dipole interactions.
## the chemical nature of the solute.
## none of these.
# The standard enthalpy of combustion of acetylene (C{~}2{~}H{~}2~) is \-1410 kJ/mol. How many kJ of heat are liberated by the combustion of 13.0 g of acetylene?
## 13 kJ
## 705 kJ
## 18,326 kJ
## 1410 kJ
## 780 kJ
# The standard enthalpy of formation of CO (g) refers to the DH of which reaction below?
## 2 C (graphite) + O2(g) \--> 2 CO(g)
## C (diamond) + 1/2 O(g) \--> CO(g)
## C (graphite) + 1/2 O2(g) \--> CO(g)
## C (graphite) + O2(g) \--> CO(g)
# Identify the *INCORRECT* statement below:
## Energy is the capacity to do work or transfer heat.
## According to the First Law of Thermodynamics, the total amount of energy in the universe is constant.
## Endothermic processes require the absorption of energy to occur, corresponding to a positiveDH.
## The Gibbs free energy G of a system is increasing in any spontaneous process.
# A chemical reaction taking place in a calorimeter causes the temperature to rise 7.5° C. The addition of 50 kJ of energy to the same calorimeter by an electrical heater increases its temperature 2.5° C. What is DH of the chemical reaction?
## 16.7 kJ
## \-16.7 kJ
## \-150 kJ
## 150 kJ

h2. KEY

1)2
2)4
3)1
4)2
5)4
6)4
7)2
8)2
9)2
10)3
11)4
12)3