1. How many atoms of hydrogen are found in 8.58 mol of heptane, C7H16?

2. How many atoms of carbon are combined with 9.59 moles of hydrogen atoms in a sample of the compound methane, CH₄?

3. It was found that 4.51 g of a compound of phosphorus and chlorine contained 0.893 g of phosphorus. What are the percentages by mass of phosphorus and chlorine in this compound?

19.8% P and 80.2% Cl

35.0% P and 65.0% Cl

10.5% P and 89.5% Cl

20.6% P and 79.4% Cl