Question

determine how many grams of N2 are produced from the reaction of 8.75 g of H2O2 and 5.43 g of N2H4.

2H2O2+N2H4 4H2O+N2


g N2?

Answer 1

2H2O2 + N2H4 --> 4H2O + N2

This is a limiting reagent (LR) problem. You know that when amounts are given for BOTH reactants.

mols H2O2 = grams/molar mass = approx 0.26 but that's just an estimate. You should redo ALL of these calculations for all are estimates.

mols N2H4 = approx 0.17

Using the coefficients in the balanced equation, convert mols H2O2 to mols of the product (in this case N2). That is
approx 0.26 x (1 mol N2/2 mols H2O2) = approx 0.13

Do the same to convert mols N2H4 to mols N2. You can go through the math but that's approx 0.17 x (1 mol N2/1 mol N2H4) - approx 0.17

In LR problems the answer is ALWAYS the smaller one so N2H4 is the LR and H2O2 is the excerss reagent.

So take the smaller value, convert to grams of the product.
mols N2 x molar mass N2 = grams N2.

Post your work if you get stuck.

Answer 2

ok so far I have gotten

0.257 mol H2O2

0.169 mol N2H4

Im not sure where to go after this

Answer 3

This step follows to convert mols H2O2 to mols N2.

<b>Using the coefficients in the balanced equation, convert mols H2O2 to mols of the product (in this case N2). That is
approx 0.26 x (1 mol N2/2 mols H2O2) = approx 0.13 </b>

Then do this step to convert mols N2H4 to mols N2.
<b>Do the same to convert mols N2H4 to mols N2. You can go through the math but that's approx 0.17 x (1 mol N2/1 mol N2H4) - approx 0.17

The smaller number tells you that N2H4 is the limiting reagent. So take that many mols you calculate and
mols N2 x molar mass N2 = grams N2.</b>