Questions: Multiply or divide the following measurements. Be sure each answer you enter contains the correct number of significant digits. 788.5 g / 0.58 mL = □ g/mL 495.12 mol / 70.5 L = □ mol/L 78.1 mol/L × 18 L = □ mol

Solution Steps

To find the result of \( 788.5 \, \text{g} \div 0.58 \, \text{mL} \), we need to divide the mass by the volume. The number of significant digits in the result should be determined by the measurement with the fewest significant digits. Here, \( 788.5 \, \text{g} \) has four significant digits, and \( 0.58 \, \text{mL} \) has two significant digits. Therefore, the result should have two significant digits.

\[ \frac{788.5 \, \text{g}}{0.58 \, \text{mL}} = 1360.3448276 \, \frac{\text{g}}{\text{mL}} \]

Rounding to two significant digits, we get:

\[ \boxed{1400 \, \frac{\text{g}}{\text{mL}}} \]

For \( 495.12 \, \text{mol} \div 70.5 \, \text{L} \), we divide the moles by the volume. The number of significant digits in the result should be determined by the measurement with the fewest significant digits. Here, \( 495.12 \, \text{mol} \) has five significant digits, and \( 70.5 \, \text{L} \) has three significant digits. Therefore, the result should have three significant digits.

\[ \frac{495.12 \, \text{mol}}{70.5 \, \text{L}} = 7.02212766 \, \frac{\text{mol}}{\text{L}} \]

Rounding to three significant digits, we get:

\[ \boxed{7.02 \, \frac{\text{mol}}{\text{L}}} \]

For \( 78.1 \, \frac{\text{mol}}{\text{L}} \times 18 \, \text{L} \), we multiply the concentration by the volume. The number of significant digits in the result should be determined by the measurement with the fewest significant digits. Here, \( 78.1 \, \frac{\text{mol}}{\text{L}} \) has three significant digits, and \( 18 \, \text{L} \) has two significant digits. Therefore, the result should have two significant digits.

\[ 78.1 \, \frac{\text{mol}}{\text{L}} \times 18 \, \text{L} = 1405.8 \, \text{mol} \]

Rounding to two significant digits, we get:

\[ \boxed{1400 \, \text{mol}} \]

Final Answer