Sabtu, 01 Agustus 2009

BOILING POINT AND FREEZING POINT

1.Dissolving 1 mole of KCl in 1000 grams of H2O affects
a) the boiling point of the H2O, only
b) the freezing point of the H2O, only
c) both the boiling point and the freezing point of the H2O
d) neither the boiling point nor the freezing point of the H2O
2.Which solution has the highest boiling point?
a) 1.0 M Ca(NO3)2
b) 2.0 M Ca(NO3)2
c) 1.0 M KNO3
d) 2.0 M KNO3
e) 4.0 M KNO3
3.If 4.27 grams of sucrose, C12H22O11 (molar mass = 342 g/mol), is dissolved in 15.2 grams of water, what will be the boiling point of the resulting solution? Kb for water is 0.512°C/molal. Assume the barometric pressure is 760 torr, at which pure water has a boiling point of 100.000°C.
a) 101.64°C
b) 100.42°C
c) 99.626°C
d) 100.73°C
e) 101.42°C
4.Which of the following solutes will produce the highest solution boiling point when dissolved in water?
a) 2 moles of NaCl
b) 1 mole of ethanol
c) 1 mole of MgCl2
d) 2 moles of methanol
e) 1 mole of methanol
5.Rank the following liquids in order of increasing boiling points, from lowest to highest:
n-pentane (C5H12)
hexyl alcohol (C6H13OH)
2,2-dimethylpropane (C5H12)
a) n-pentane (C5H12) < hexyl alcohol (C6H13OH) < 2,2-dimethylpropane (C5H12)
b) 2,2-dimethylpropane (C5H12) < n-pentane (C5H12) < hexyl alcohol (C6H13OH)
c) hexyl alcohol (C6H13OH) < 2,2-dimethylpropane (C5H12) < n-pentane (C5H12)
d) n-pentane (C5H12) < 2,2-dimethylpropane (C5H12) < hexyl alcohol (C6H13OH)
e) 2,2-dimethylpropane (C5H12) < hexyl alcohol (C6H13OH) < n-pentane (C5H12)
6.The boiling point of O2 is higher than N2 due to:
a) ion-dipole forces.
b) dipole-dipole forces.
c) hydrogen bonding.
d) London forces.
e) ion-ion forces.
7.Calculate the freezing point of a solution that contains 8.00 g of sucrose, C12H22O11 (molar mass = 342 g/mol), in 100.0 g of H2O. Kf for H2O is 1.86°C/molal.
a) -0.044°C
b) -0.22°C
c) -0.39°C
d) -0.44°C
e) 0.040°C
8.Which of the following solutes will produce the lowest solution freezing point when dissolved in water?
a) 2 moles of KNO3
b) 1 mole of ethanol
c) 1 mole of CaCl2
d) 2 moles of methanol
e) 1 mole of methanol
9.Calculate the mass of "antifreeze" (ethylene glycol, MW (molar mass) = 62 g/mol) necessary to mix with 80 L (80 Kg) of water in a radiator in order to make the water in the radiator freeze below 0oF (-17.8oC). Kf for water is -1.86oC/m.
a) 48 kg
b) 80 kg
c) 62 g
d) 4800g
e) 2400g
10.Which of the following solutes will produce the highest freezing point when dissolved in water?
a)4 grams of NaOH in 1L of water
b)3 grams of urea in 2L of water
c)18 grams of glucose in 500 mL of water
d)5,9 grams of NaCl in 2L of water
e)1,5 grams of acetic acid in 500 mL of water

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