How many hydrogen atoms are in 1.5 moles of carbon tetrahybride?

Question

I really don't understand this question. Please help. 

Answer 1

Carbon tetrahydride is a fancy name for methane. Its formula is CH4. A mole is a special name for a quantity of something. You are familiar with the word "dozen". We know that means 12. A dozen eggs is 12 eggs. A dozen cars is 12 cars. A mole of something means that there are 6.02 X 10^23 of that something. So, a mole of methane molecules is 6.02 X 10^23 methane molecules. So, 1.5 moles of methane will contain 1.5*(6.02 X 10^23) =  9.0 X 10^23 methane molecules. But, since the formula for methane is CH4, there are 4 hydrogen atoms for each methane molecule. Thus, 1.5 moles of methane contain 4*(9.0 X 10^23) = 3.6 X 10^24 hydrogen atoms. By the way, I am performing my calculations to watch my significant figures, which is so important in Chemistry.