Question

1) Compared to other main group hydrides, such as CH4, NH3, H2S and HF, water is unique because it is a liquid at room temperature. The most likely explanation for this is that:

a)Water is more plentiful than any of these other compounds.

b)Water contains oxygen and since oxygen has a high boiling point, so should water.

c)Water's structure allows for the formation of multiple hydrogen bonds with other molecules, including itself.

d)Water is able to dissolve nonpolar gases like oxygen and carbon dioxide.


2)Calculate the freezing point of a 2.6-molal aqueous sucrose solution. The freezing point depression constant for water is 1.86 degrees C/molal.


a)4.8 °C

b)1.4 °C

c)-1.4 °C

d)-4.8 °C


3)A solution containing one mole of glucose (C6H12O6) and a separate solution containing one mole of sucrose (C12H22O11), are each dissolved in one kilogram of water. Both solutions exhibit the same colligative properties. How is this possible?


a)Each solution has the same number of relative particles of solute per kilogram of solvent.

b)Each solute has a comparable molecular mass.

c)Each solute has the same relative molecular structure.

d)Each solute has the same solubility in water.

Answer 1

1) Water's structure allows for the formation of multiple hydrogen bonds with other molecules, including itself.

2) -4.8 °C

3) Each solution has the same number of relative particles of solute per kilogram of solvent.

Step-by-step explanation:

1) the hydrogen attached to oxygen (a highly electronegative oxygen atom) thus is able to form hydrogen bond with other highly electronegative elements F,O and N. Due to this water has high boiling point as compared to other hydrides mentioned.

2) the freezing point depression is related to molality as:

Depression in freezing point = Kf X molality

depression in freezing point = 1.86 X 2.6 = 4.836

So the freezing point of aqueous solution = -4.836 °C

3) The colligative property depends upon the number of non volatile solute particles and not on nature of molar mass.

Thus both solution exhibit same collgative properties as we have taken one mole of each.

Answer 2

1. d. Water is able to dissolve non-polar gases like oxygen and carbon dioxide.

2. d. -4.8 degree Celsius

3. a. Each solution has the same number of relative particles of solute per kilogram of solvent.