Gas laws

1. A sample of unknown compound gas X is shown by analysis to contain Sulphur and Oxygen. The
gas requires 28.3 seconds to diffuse through a small aperture into a vacuum. An identical number
of oxygen molecules pass through the same aperture in 20seconds. Determine the molecular mass
of gas X (O= 16, S= 32)
2. (a) State Graham’s Law of diffusion
(b) Gas V takes 10 seconds to diffuse through a distance of one fifth of a meter. Another
gas W takes the same time to diffuse through a distance of 10 cm. if the relative molecular
mass of gas V is 16.0; calculate the molecular mass of W
3. (a) State Charles’ Law
(b) The volume of a sample of nitrogen gas at a temperature of 291K and 1.0 x 10^5 Pascals
was 3.5 x 10-2m3. Calculate the temperature at which the volume of the gas would be
2.8 x 10^-2 m3 at 1.0 x 10^5 pascals.
4. 60 cm3 of oxygen gas diffused through a porous partition in 50 seconds. How long would it take
60 cm3 of sulphur (IV) oxide gas to diffuse through the same partition under the sane conditions?
(S = 32.0, O = 16.0)
5. (a) State Graham’s law of diffusion
(b) 30cm3 of hydrogen chloride gas diffuses through a porous pot in 20seconds. How long
would it take 42cm3 of sulphur(IV) oxide gas to diffuse through the same pot under
the same conditions (H =1 Cl = 35.5 S = 32 O =16)
6. a) State Boyles law
b) Sketch a graph that represents Charles’ law
c) A gas occupied a volume of 250cm3 at -23ºC and 1 atmosphere. Determine its volume
at 127ºC when pressure is kept constant.
7. A factory produces Calcium Oxide from Calcium Carbonate as shown in the equation below:-
CaCO3 (s)--------> CaO (s) + CO2 (g)
(a) What volume of Carbon (IV) Oxide would be produced from 1000kg of Calcium
Carbonate at s.t.p (Ca = 40, C = 12, O = 16, Molar gas volume at s.t.p = 22.4dm3)
8. A fixed mass of gas occupies 200cm3 at a temperature of 23oC and pressure of 740mmHg.
Calculate the volume of the gas at -25 degrees C and 780mmHg pressure
9. Gas K diffuses through a porous material at a rate of 12cm3 s-1 where as S diffuses through
the same material at a rate of 7.5cm3s-1. Given that the molar mass of K is 16, calculate the
molar mass of S
10. (a) State Gay Lussac’s law
. 11. (a) What is the relationship between the rate of diffusion of a gas and its molecular mass?
(b) A sample of Carbon (IV) Oxide takes 200 seconds to diffuse across a porous plug.
How long will it take the same amount of Carbon (II) Oxide to diffuse through the
same plug?(C=12, O=16)
12. Below are structures of particles. Use it to answer questions that follow. In each case only
electrons in the outermost energy level are shown

(a) Identify the particle which is an anion
(b) Choose a pair of isotopes. Give a reason
13. The figure below shows two gases P and Q diffusing from two opposite ends 18 seconds after
the experiment

(a) Which of the gases has a lighter density?
(b) Given that the molecular mass of gas Q is 17, calculate the molecular mass of P
14. Identify the particles that facilitate the electric conductivity of the following substances
(i) Sodium metal
(ii) Sodium Chloride solution
(iii) Molten Lead Bromide
15. Gas B takes 110 seconds to diffuse through a porous pot, how long will it take for the
same amount of ammonia to diffuse under the same conditions of temperature and pressure?
(RMM of B = 34 RMM of ammonia = 17)
16. A gas occupies 5dm3 at a temperature of -27 degrees C and 1 atmosphere pressure. Calculate the
volume occupied by the gas at a pressure of 2 atmospheres and a temperature of 127 degress C
17. A fixed mass of gas occupies 200 cm3 at a temperature of 230c and a pressure of 740 mm Hg.
Calculate the volume of the gas at -25 degrees c and 790 mm Hg pressure.
18. (a) State the Graham’s law
(b) 100cm3 of Carbon (IV) oxide gas diffused through a porous partition in 30seconds.
How long would it take 150cm3 of Nitrogen (IV) oxide to diffuse through the same
partition under the same conditions? (C = 12.0, N = 14.0, O = 16.0)