To determine which compound contains the greatest percentage of sodium (Na) by mass, we need to calculate the percentage of sodium in each compound. Here are the molar masses of the compounds given:
- NaCN: 49.0 g/mol
- NaN₃: 65.0 g/mol
- NaOH: 40.0 g/mol
- NaCl: 58.4 g/mol
The molar mass of sodium (Na) is 22.99 g/mol.
Now let's calculate the percentage of sodium in each compound:
1. NaCN:
Percentage of sodium = [tex]\(\left(\frac{\text{Molar mass of Na}}{\text{Molar mass of NaCN}}\right) \times 100\)[/tex]
[tex]\[
= \left(\frac{22.99}{49.0}\right) \times 100 \approx 46.92\%
\][/tex]
2. NaN₃:
Percentage of sodium = [tex]\(\left(\frac{\text{Molar mass of Na}}{\text{Molar mass of NaN₃}}\right) \times 100\)[/tex]
[tex]\[
= \left(\frac{22.99}{65.0}\right) \times 100 \approx 35.37\%
\][/tex]
3. NaOH:
Percentage of sodium = [tex]\(\left(\frac{\text{Molar mass of Na}}{\text{Molar mass of NaOH}}\right) \times 100\)[/tex]
[tex]\[
= \left(\frac{22.99}{40.0}\right) \times 100 \approx 57.48\%
\][/tex]
4. NaCl:
Percentage of sodium = [tex]\(\left(\frac{\text{Molar mass of Na}}{\text{Molar mass of NaCl}}\right) \times 100\)[/tex]
[tex]\[
= \left(\frac{22.99}{58.4}\right) \times 100 \approx 39.37\%
\][/tex]
Summarizing the percentages:
- NaCN: 46.92%
- NaN₃: 35.37%
- NaOH: 57.48%
- NaCl: 39.37%
From the calculations, we can see that NaOH has the greatest percentage of sodium by mass, which is approximately 57.48%.
Thus, the compound that contains the greatest percentage of sodium by mass is:
(C) NaOH
