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Gases questions

Gases questions | form five Chemistry

Find Gases examination questions, form five Chemistry in acaproso.com

# Question
1

Use the kinetic gas equation to explain the following concepts

  1. The pressure exerted by an ideal gas increases when it is heated at a constant volume.
  2. The volume occupied by an ideal gas increases when it is heated at constant pressure.

Short answers
2

A flammable gas made up of only carbon and hydrogen is generated by certain anaerobic bacteria in sewage drains. A pure sample of a gas was found to effuse through a certain porous barriers in 1.50 minutes. Under the same conditions of temperature and pressure it takes 4.73 minutes for an equal volume of bromine gas to effuse through the same barrier . Calculate the molar mass of the unknown gas and suggest the name of the gas. (Molecular mass of Bromine is 159.8 g/m)


Mathematical Calculation
3

In the determination of the molecular weight of chloroform  vapour by Hofmann`s method , the following results were obtained :

Weight of liquid in bulb =0.2704 g, Volume of vapour =110 cm3 ; Temperature of vapour =99.6 °C; Atmospheric pressure =747 mmHg; Vapour pressure of water vapour at 99.6°C =285.2 mmHg. Calculate the the relative molecular weight of chloroform if 1 dm3 of H2 at S.T.P weighs 0.09 g. In your calculations, show your work clearly including manipulations of units.


Mathematical Calculation
4

The equilibrium constant for the reaction Co(g)+H_{2}O(g) 
ightleftharpoons CO_{2}(g)+H_{2}(g) at 986°C is 0.63. A mixture of 1.0 mole of water vapour and 3.0 mole of CO is allowed to come to equilibrium . The equilibrium pressure is 2.0 atm.

  1. Calculate the number of moles of H2 present at equilibrium.
  2. Calculate the partial pressure of gases at equilibrium mixture.

Mathematical Calculation
5

A 0.25 moles of air has entered a diesel engine at a pressure of 1.05x105 Pa and a temperature of 27oC. Assuming that air is ideal, calculate:

  1. The volume it occupies.
  2. Its temperature, immediately after compression to one twentieth of its original volume where the pressure rises to 7.0x106Pa.

Mathematical Calculation
6

A 42g of nitrogen gas and 8g of hydrogen gas are mixed in a 10 litre vessel at 20oC. Calculate the partial pressure of each gas and the total pressure of the gas mixture.


Mathematical Calculation
7

State the following gas laws , then provide their mathematical expressions:

  1. Boyle`s law.
  2. Charles` law.
  3. Graham`s laws.
  4. Dalton`s law of partial pressures.

Short answers
8

State five assumptions of the kinetic theory of gases.


Short answers
9

50cm3 of carbon dioxide at 1x105 Nm-2 are mixed with 150cm3 of hydrogen at the same pressure. If the pressure of the mixture is 1.0x105 Nm-2 , calculate the partial pressure of hydrogen gas.


Mathematical Calculation
10

In 5 minutes, 15cm3 of argon effuse through a pinhole. What volume of xenon will effuse thhrough the same pinhole under the same condition? [Atomic masses: Ar=39.95, Xe=131.29]


Mathematical Calculation