Attempt 2 A sample of gas contains 49.16 % N 2 gas, 19.85 % Br 2 gas, 9.95 % CO 2 gas, and 21.04 % of an unknown gas. The average atomic mass of the gas mixture is 50.71 u. Calculate the atomic mass of the unknown gas.

Atomic mass of unknown gas is 4u

Explanation:

Average atomic mass of a gas is defined as the sum of molecular mass * percentage of each component in the mixture.

In the problem:

50.71u = 28*49.16% + 159.8*19.85% + 44*9.95% + X*21.04%

Where X is atomic mass of unknown gas

50.71u = 49.86 + X*21.04%

0.8469 = X*21.04%

4u = X

Atomic mass of unknown gas is 4u

The atomic mass of the unknown gas is 3.982 u

Explanation:

Step 1: Data given

A gas contains:

49.16 % N2 gas

19.85 % Br2 gas

9.95 % CO2 gas

21.04 % of an unknown gas

The average atomic mass of the gas mixture is 50.71 u

Molar mass of N2 = 28.0134 u

Molar mass of Br2 = 159.808 u

Molar mass of CO2 = 44.009 u

Step 2: Calculate tthe atomic mass of the unknown gas

50.71 = 0.4916 * 28.0134 + 0.1985 * 159.808 + 0.0995 * 44.009 + 0.2104 * X

50.71 = 13.77138744 + 31.721888 + 4.3788955 + 0.2104 X

0.83782906 = 0.2104X

X = 0.83782906 / 0.2104

X = 3.982 u

The atomic mass of the unknown gas is 3.982 u