Question

How many atoms of hydrogen are there in 3.0kg of ethane

Answer 1

Ethane has the formula C2H6.
From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of hydrogen = 1 gram
Therefore:
molar mass of ethane = 2(12) + 6(1) = 30 grams

This means that each 30 grams of ethane contains 6 grams of hydrogen. To know how many grams of hydrogen are in 3000 grams of ethane (3 kg), we will simply use cross multiplication as follows:
mass of hydrogen = (3000 x 6) / 30 = 600 grams