Question

Use the balanced chemical equation to answer the question.
Which is the correct mole ratio for calculating the mass of hydrogen peroxide (
) needed toproduce a certain mass of oxygen (
)?
(1 point)
2H2O2 → 2H2O + O2
H2O2
O2
/
1
O
2
1
H
2
O
2
/
2
H
2
O
2
2
O
2
/
1
H
2
O
2
2
O
2
/
2
H
2
O
2
1
O
2
A)
Which action can be taken to find the number of moles of a substance equivalent to 20 g?
(1 point)
Multiply 20 g by Avogadro’s number.
Divide 20 g by the molar mass of the substance.
Divide 20 g by Avogadro’s number.
Multiply 20 g by the molar mass of the substance.

Answer 1

1) Use the reaction 2 H2O2 → 2 H2O + O2. The correct mole ratio is 2 mol H2O2 / 1 mol O2 (i.e., 2 H2O2 per 1 O2).

2) Divide 20 g by the molar mass of the substance (moles = mass / molar mass).