# SK015 CHAPTER 5.1 : Gas

### Ideal Gas Law

#### Example 1

State the relationships of the volume of an ideal gas with its pressure, absolute temperature and the amount of gas respectively. A student added an amount of hydrochloric acid to a rock sample and observed the fizzing action indicating a gas being released. At 25oC, the gas collected in a 0.220 L gas bulb was 0.300 g and at a pressure of 0.757 atm. Calculate the molar mass and the density of this gas.

Example 2

In the offshore base oil drilling operation, methane gas, CHwas found at the bottom of the sea at 480oC and a pressure of 12.8 atm.

• Calculate the volume of gas needed to be transferred to a container in the refinery mill with a volume of 1.80 x 10L at a pressure of 1.0 atm and temperature of 22oC.

• Determine the mass of the gas being transferred.

### Dalton's Law

#### Example 3

Ethene, C2H6, burns in the air according to the equation below:

2C2H(g) + 7O(g) 4CO(g) + 6H2O(g)

A mixture of C2Hand Oat 30 mmHg and 124 mmHg respectively, was added into a 7.5 L flask at a temperature of 27oC. The combustion reaction was carried out until completion.

Calculate the total pressure of the gas mixture obtained at the end of the reaction, at the same temperature. Give your answer in mmHg.