I need help with two science questions.

Question

How many moles of O_2(g) are required to react with 2 mol C₆H_6(l) to produce 12 mol CO_2(g) and 6 mol H₂O_(g)?

How many moles of O_2(g) are required to react with 4 mol C₆H_6(l) to produce 24 mol CO_2(g) and 12 mol H₂O_(g)?



Answer 1

Both questions involve the combustion of C6H6 to produce CO2 and H2O. First, you MUST write the balanced equation for the reaction:

2C₆H₆ + 15O₂ ===> 12CO₂ + 6H₂O ... balanced equation

This tells you that 2 moles C₆H₆ react with 15 moles O₂ to produce 12 moles CO₂ and 6 moles H₂O

1) How many moles O₂ needed to react with 2 mol C₆H₆?

2 mole C₆H₆ x 15 moles O₂/2 moles C₆H₆ = 15 moles O₂ needed

2) How many moles O₂ needed to react with 4 mol C₆H₆?

4 moles C₆H₆ x 15 moles O₂/2 moles C₆H₆ = 30 moles O₂ needed