A chemist determined by measurements that 0.075 moles of barium participated in a chemical reaction. Calculate the mass of barium that participated in the chemical reaction.

Be sure your answer has the correct number of significant digits.

1 answer

To calculate the mass of barium that participated in the chemical reaction, you need to use the molar mass of barium. The molar mass of barium (Ba) is approximately 137.33 g/mol.

Given:
- Moles of barium (\( n \)) = 0.075 mol
- Molar mass of barium (\( M \)) = 137.33 g/mol

The mass (\( m \)) of barium can be calculated using the formula:
\[ m = n \times M \]

Now, substituting the values:
\[ m = 0.075 \, \text{mol} \times 137.33 \, \text{g/mol} \]

\[ m = 10.29975 \, \text{g} \]

Since the given number of moles (0.075) has two significant digits, the mass should also be reported with two significant digits. Hence, we round 10.29975 g to two significant digits:

\[ m \approx 10 \, \text{g} \]

Therefore, the mass of barium that participated in the chemical reaction is approximately **10 grams**.