Worksheet 5.docx

CHM1102 – Worksheet 5 Solutions 1. State Boyle’s Law in words and mathematically 2. State Charles’ Law in words and mathematically 3. State Avogadro’s Law in words and mathematically

(ii) 1 pressure/atm

Temperature/K

(iii)

temperature /oC

(v)

Volume /dm3

(iv)

Volume /m3

pressure/atm Volume /cm3

Volume /m3

(i)

Volume /cm3

Volume /dm3

4. Which of the graphs below illustrate the gas laws?

1 temperature/oC

(vi) 1 temperature/K

5. A chemist prepared a sample of hydrogen bromide and found that it occupied 255 ml at 850C and 600 Torr. What volume would it occupy at 00C at the same pressure? 6. i.) Complete the following table for an ideal gas: (a) (b) (c) (d)

P (atm) 5.00 0.300 4.47

Vol. (L) 2.00 25.0 2.25

n (mol) 2.0 2.01 10.5

Temp. 1550C 155K 750C

pV = nRT; R = 0.08206 LatmK-1mol-1; R = 8.314 JK-1mol-1 ii) If the sample of gas in (b) has a mass of 3.35g, calculate the molar mass of the gas. This is a homonoid diatomic molecule. Deduce the name of the gas.

7. Methane reacts with oxygen according to the following equation:

CH4 (g) + 1 ½O2 (g) → CO(g) + 2H2O(g) At a constant temperature of 373K and pressure of 1.00 atm, 100 cm3 of methane and 300 cm3 of oxygen are placed in a sealed container; Calculate (a) the volumes of carbon monoxide and water vapour produced (b) the total volume of gas in the container at the end of the process (c) the partial pressure of oxygen at the end of the process. 8. Assume that you have a cylinder with a moveable piston. What would happen to the gas volume of the cylinder if you were to do the following? (a) Halve the Kelvin temperature while holding the pressure constant. (b) Increase the amount of gas by 1/4 while holding the temperature and pressure constant. (c) Decrease the pressure by 75% at constant T. (d) Double the Kelvin temperature and double the pressure.