What is the percent by mass of sodium in NaCl?
Understand the Problem
The question is asking for the calculation of the percent by mass of sodium in sodium chloride (NaCl). To solve this, we need to determine the molar mass of Na and Cl, then use the formula for percent by mass which is (mass of sodium / mass of NaCl) * 100.
Answer
$39.38\%$
Answer for screen readers
The percent by mass of sodium in sodium chloride (NaCl) is approximately $39.38%$.
Steps to Solve
- Calculate the molar mass of sodium (Na)
To find the molar mass of sodium, we look at the periodic table. The atomic mass of sodium (Na) is approximately 22.99 g/mol.
- Calculate the molar mass of chlorine (Cl)
Next, we find the molar mass of chlorine. The atomic mass of chlorine (Cl) is approximately 35.45 g/mol.
- Calculate the molar mass of sodium chloride (NaCl)
Now, we add the molar masses of sodium and chlorine to find the molar mass of NaCl:
$$ \text{Molar mass of NaCl} = \text{Molar mass of Na} + \text{Molar mass of Cl} $$
Substituting the values:
$$ \text{Molar mass of NaCl} = 22.99 , \text{g/mol} + 35.45 , \text{g/mol} \approx 58.44 , \text{g/mol} $$
- Calculate the percent by mass of sodium in NaCl
Now we use the formula for percent by mass:
$$ \text{Percent by mass of Na} = \left( \frac{\text{mass of Na}}{\text{mass of NaCl}} \right) \times 100 $$
Substituting the values:
$$ \text{Percent by mass of Na} = \left( \frac{22.99 , \text{g/mol}}{58.44 , \text{g/mol}} \right) \times 100 $$
- Compute the value
Now calculate the percent:
$$ \text{Percent by mass of Na} \approx \left(0.39379\right) \times 100 \approx 39.38% $$
The percent by mass of sodium in sodium chloride (NaCl) is approximately $39.38%$.
More Information
Sodium chloride, commonly known as table salt, is essential for various biological functions. The calculated percent by mass shows that sodium constitutes a significant part of NaCl.
Tips
- Forgetting to add the molar masses correctly might lead to an incorrect calculation of the molar mass of NaCl.
- Misplacing decimal points in percentages can alter the final answer, so it’s essential to check calculations.
