Question

Calculate the average molecular weight of air (1) from its approximate molar composition of 79% N2, 21% 02x

Answer 1

Answer:

Average molecular weight of air is 28.84 g/mol.

Explanation:

The average molecular weight of a mixture is determined from their molar composition and molecular weight.

Average molecular weight :$\sum (\chi_i\times m_i)$

$\chi_1$ : mole fraction of the 'i' component.

$m_i$ = Molecular weight of i component

Average molecular weight of air with approximate molar composition of 79% nitrogen gas and 21% of oxygen gas can be calculated as:

Average molecular weight of air:

$79\%\times 28 g/mol+21\%\times 32 g/mol$

$=0.79\times 28 g/mol+0.21\times 32 g/mol=28.84 g/mol$