Questions: The density of ethanol, a colorless liquid that is commonly known as grain alcohol, is 0.798 g/mL. Calculate the mass of 21.8 mL of the liquid in grams. Be sure your answer has the correct number of significant digits. g

Solution Steps

We are given the density of ethanol and the volume of ethanol. The values are:

• Density, \( \rho = 0.798 \, \frac{\mathrm{g}}{\mathrm{mL}} \)
• Volume, \( V = 21.8 \, \mathrm{mL} \)

The formula to calculate mass from density and volume is: \[ m = \rho \times V \]

Substitute the given values into the formula: \[ m = 0.798 \, \frac{\mathrm{g}}{\mathrm{mL}} \times 21.8 \, \mathrm{mL} \]

Perform the multiplication to find the mass: \[ m = 0.798 \times 21.8 = 17.4164 \, \mathrm{g} \]

The volume \( 21.8 \, \mathrm{mL} \) has three significant digits, so the final answer should also have three significant digits: \[ m \approx 17.4 \, \mathrm{g} \]

Final Answer