The mass of a 132 by mass solution is 872 g the

1. The mass of a 13.2% (by mass) solution is 8.72 g. The density of the solution is 1.984
g/mL. What is the mass of the water in this solution?
A) 10 g B) 2.28 g C) 7.57 g D) 15 g E) 0.00757 kg
2. The volume of a 24.0% (by mass) solution is 68.4 mL. The density of the solution is 1.552
g/mL. What is the mass of the solution?
3. What mass of a 31.0% by mass glucose, C
6
H
12
O
6
, solution contains 50.0 g of glucose?

4. What is the percent Na
2
CO
3
by mass in a 1.56 molal aqueous solution?
5. What is the molality of a 10.0% by mass hydrochloric acid solution? The density of the
solution is 1.0474 g/mL.
A) 3.05 m B) 2.87 m C) 0.0105 m D) 0.100 m E) 2.64 m

UNIT-10 GASES AND SOLUBILITY
Non-polar gases are usually not soluble in water. Most of the gases such as CO
2
, O
2
, N
2
and H
2
are not soluble in water because they are non-polar molecules. However, certain amount of these
gas molecules is soluble in water mainly because of dispersion and polar-induced dipole
interactions between non-polar gas and polar water molecules. By reducing the temperature, it is
possible to increase the solubility of gas molecules in polar solvents. Also, by increasing the
pressure in closed containers, it is also possible to force the gas molecules to get dissolved in
water. It should be remembered that the reduced temperature or increased pressure are temporary
conditions to improve the solubility. Once we remove these artificial conditions, the gas molecules
will slowly evaporate from polar solvent. The carbonated soda is an ideal example where CO
2
is
forced to dissolve in water by reducing temperature and increasing the pressure.
CTQ-1: List all possible intermolecular interactions in carbonated soda that has only CO
2
and
H
2
O.
Effect of Temperature and Pressure on Solibility:
Henry’s law: William Henry in 1803 proposed that the solubility of a gas in a solvent is directly
proportional to the partial pressure of the gas in contact with the solution. We can write this as:
S = k. P where S is solubility, k is the proportionality constant and
P is partial pressure above the gas.
The Henry’s constant ( k ) is characteristic for any particular gas as it interacts with pure water. Some
values for k
H
for gases dissolved in water at 298 K include:
Oxygen (O
2
) : 769.2 L · atm / mol ;
Carbon dioxide (CO
2
) : 29.41 L·atm/mol;
Hydrogen (H
2
) : 1282.1 L·atm/mol
Henry’s constant is written in two versions of units.
1. (L.atm)/mol k= P/S
2. Mol/(L.atm) k = S/P