What is the mass (in grams) of 500 mL of ethanol? (density of ethanol = 0.789 g/mL)

Explanation

Step 1: Write the density formula
Density = Mass / Volume
Rearranging: Mass = Density × Volume

Step 2: List the given values
Density of ethanol = 0.789 g/mL
Volume of ethanol = 500 mL

Step 3: Calculate the mass
Mass = 0.789 g/mL × 500 mL
Mass = 394.5 g

Key Point: Ethanol is less dense than water (which has density 1.0 g/mL). The same volume of ethanol weighs less than the same volume of water would weigh.