20. The density of copper is 8.94 g per cubic centimeter. Express the density of copper in kilograms per cubic centimeter. What is the density in kilograms per liter? (Hint: 1 cubic centimeter has a volume of 1 millimeter.)

To solve the problem, we need to convert the density of copper from grams per cubic centimeter to kilograms per cubic centimeter and then to kilograms per liter. ### Step 1: Convert grams per cubic centimeter to kilograms per cubic centimeter 1. **Known condition**: The density of copper is given as \( 8.94 \, \text{g/cm}^3 \). 2. **Conversion factor**: \( 1 \, \text{kg} = 1000 \, \text{g} \). To convert grams to kilograms, we divide by 1000: \[ \text{Density in kg/cm}^3 = \frac{8.94 \, \text{g/cm}^3}{1000} = 0.00894 \, \text{kg/cm}^3 \] ### Step 2: Convert kilograms per cubic centimeter to kilograms per liter 1. **Known condition**: \( 1 \, \text{cm}^3 = 1 \, \text{mL} \) and \( 1 \, \text{L} = 1000 \, \text{mL} \). 2. Therefore, \( 1 \, \text{L} = 1000 \, \text{cm}^3 \). To convert from kg/cm³ to kg/L, we multiply by 1000: \[ \text{Density in kg/L} = 0.00894 \, \text{kg/cm}^3 \times 1000 = 8.94 \, \text{kg/L} \] ### Final Results - The density of copper in kilograms per cubic centimeter is \( 0.00894 \, \text{kg/cm}^3 \). - The density of copper in kilograms per liter is \( 8.94 \, \text{kg/L} \).