Question

1. choose the best answer. a student compared a mole of water (h₂o) molecules to a mole of h₂o₂ molecules. which two statements are true? both samples have the same number of hydrogen atoms. both samples have an equal number of molecules. both samples have an equal number of oxygen atoms. both samples have twice as many oxygen atoms as hydrogen atoms.

Explanation:

Step1: Analyze molecule count per mole

1 mole of any substance contains $6.022 \times 10^{23}$ molecules, so 1 mole of $\text{H}_2\text{O}$ and 1 mole of $\text{H}_2\text{O}_2$ have equal numbers of molecules.

Step2: Count hydrogen atoms per mole

For $\text{H}_2\text{O}$: 2 H atoms per molecule, so total H atoms = $2 \times 6.022 \times 10^{23}$
For $\text{H}_2\text{O}_2$: 2 H atoms per molecule, so total H atoms = $2 \times 6.022 \times 10^{23}$
Thus, both samples have the same number of hydrogen atoms.

Step3: Count oxygen atoms per mole

For $\text{H}_2\text{O}$: 1 O atom per molecule, total O atoms = $1 \times 6.022 \times 10^{23}$
For $\text{H}_2\text{O}_2$: 2 O atoms per molecule, total O atoms = $2 \times 6.022 \times 10^{23}$
So oxygen atom counts are not equal, and $\text{H}_2\text{O}$ does not have twice as many O as H atoms.

Answer:

• Both samples have the same number of hydrogen atoms.
• Both samples have an equal number of molecules.