Question

Calculate the average molecular weight of the mixture of 25% CH4 and 75% SO2 by volume

Answer 1

at constant temperature and pressure,

% of volume of gas = % of mole of gas [ yes of course , it is Avogadro's law ]

Let mass of mixture is 100g

then, mass of CH4 = 25% of 100g = 25g

mass of SO2 = 75% of 100 = 75 g

now, number of mole of CH4 = weight in gm/molecular weight

= 25g/(16g/mol)

= (25/16) mol

number of mole of SO2 = 75g/(64g/mol)

= (75/64) mol

now, total number of mole of mixture = (25/16) + (75/64)

= (100/64) + (75/64)

= 175/64 mol

we know, mole = weight in gm/molecular weight

so, mole of mixture = weight of mixture/molecular weight of mixture

or, 175/64 = 100/molecular weight of mixture.

or, molecular weight of mixture = 6400/175 = 36.57 g/mol

Answer 2

Answer:

average molecular weight is 52

Explanation:

Average molecular weight formula -->

sigma(% abundance molecular wt. of constituent)/100

Therefore, (25×16) + (75×64)/100

= 5200/100

= 52