A compressed gas cylinder of H2 containing 25 l at 200,000 kPa of pressure is emptied due a leak in a gas chromatography laboratory, with the following dimensions: 5 m long, 4 meters wide and 2.5 m height. Calculate the % oxygen and hydrogen in the atmosphere of the laboratory after the leak. If the lower explosive limit (LEL) of H2 is 4%, is there a risk of explosion?

Taking into account the apparent volume of gas once expanded.

To calculate the percentage of oxygen and hydrogen in the atmosphere after the gas leak, we first need to determine the amount of gas that escapes from the compressed gas cylinder.

1. Calculate the initial volume of gas:
The initial volume of gas in the cylinder is given as 25 liters.

2. Calculate the final volume of gas:
Since the gas leaks into the laboratory, it will expand to fill the available space. The dimensions of the laboratory are given as 5m long, 4m wide, and 2.5m high. Multiplying these values together will give us the final volume of the gas in the laboratory.

Final volume = 5m x 4m x 2.5m

3. Calculate the expansion ratio:
The expansion ratio is the final volume divided by the initial volume.

Expansion ratio = Final volume / Initial volume

4. Calculate the amount of gas leaked:
The amount of gas leaked from the cylinder can be calculated by multiplying the initial volume of the gas by the expansion ratio.

Amount of gas leaked = Initial volume x Expansion ratio

5. Calculate the percentage of oxygen and hydrogen in the leaked gas:
Since the composition of the gas cylinder is given as hydrogen (H2), the only gas that will be present in the leaked gas is hydrogen. Therefore, the percentage of hydrogen in the leaked gas will be 100%.

The percentage of oxygen in the leaked gas can be calculated by subtracting the percentage of hydrogen (100%) from 100%.

Percentage of oxygen = 100% - Percentage of hydrogen

Once you have calculated the percentage of oxygen and hydrogen in the leaked gas, you can compare the percentage of hydrogen with the lower explosive limit (LEL) of 4% to determine if there is a risk of explosion.

If the percentage of hydrogen is greater than or equal to the LEL of 4%, there is a risk of explosion. If it is less than 4%, there is no risk of explosion.