**Mole Relations Problem #1**

Determine the number of moles of N_{2}O_{4} needed to react completely with 3.62 mol of N_{2}H_{4} for the reaction 2 N_{2}H_{4}(l) + N_{2}O_{4}(l) → 3 N_{2}(g) + 4 H_{2}O(l)

**Solution**

Find the relation between moles of N_{2}H_{4} and N_{2}O_{4} by using the coefficients of the balanced equation:

2 mol N_{2}H_{4} is proportional to 1 mol N_{2}O_{4}

Therefore, the conversion factor is 1 mol N_{2}O_{4}/2 mol N_{2}H_{4}:

moles N_{2}O_{4} = 3.62 mol N_{2}H_{4} x 1 mol N_{2}O_{4}/2 mol N_{2}H_{4}

moles N_{2}O_{4} = 1.81 mol N_{2}O_{4}

**Answer**

1.81 mol N_{2}O_{4}

**Mole Relations Problem #2**

Determine the number of moles of N_{2} produced for the reaction 2 N_{2}H_{4}(l) + N_{2}O_{4}(l) → 3 N_{2}(g) + 4 H_{2}O(l) when the reaction begins with 1.24 moles of N_{2}H_{4}.

**Solution**

Find the relation between moles of N_{2}H_{4} and N_{2} by using the coefficients of the balanced equation:

2 mol N_{2}H_{4} is proportional to 3 mol N_{2}

In this case, we want to go from moles of N_{2}H_{4} to moles of N_{2}, so the conversion factor is 3 mol N_{2}/2 mol N_{2}H_{4}:

moles N_{2} = 1.24 mol N_{2}H_{4} x 3 mol N_{2}/2 mol N_{2}H_{4}

moles N_{2} = 1.86 mol N_{2}O_{4}

**Answer**

1.86 mol N_{2}