Density
- The density of a homogeneous substance does not depend on its size or shape.
- As long as a substance is homogeneous, the density will be the same. This means that a steel nail has the same density as a cube of steel or a steel girder used to build a bridge.
- The formula for DENSITY is: mass/volume
- One milliliter takes up the same amount of space as one cubic centimeter. Therefore, density can be expressed in units of g/mL or g/cm3. Liquid volumes are most commonly expressed in milliliters, while volumes of solids are usually expressed in cubic centimeters.
- Density can also be expressed in units of kilograms per cubic meter (kg/m3).
- If you know the density of a substance and the volume of a sample, you can calculate the mass of the sample.
- To do this, rearrange the equation above to find MASS: density x volume
- If you know the density of a substance and the mass of a sample, you can find the volume of the sample.
- This time, you will rearrange the density equation to find VOLUME: mass/density
Complete the problems: 1.What is the density of a block of aluminum with a volume of 30.0 cm3 and a mass of 81.0 grams? 2. What is the mass of an iron horseshoe with a volume of 89 cm3? The density of iron is 7.9 g/cm3. 3. What is the volume of a 525-gram block of lead? The density of lead is 11.3 g/cm3. 4.Answer the following questions: Define mass Define volume Define density 5. Explain how to use the formula for calculating density. 6. Why does changing the shape of an object have no effect on the density of that object? 7. Aluminum is used to make airplanes. Cast iron is used to make weightlifting equipment. Explain why the densities of these metals make them useful for these purposes? 8. What is the density of water? Remember for water 1g=1ml=1cm3 9. Why does an air bubble rise to the surface of a glass of water? |
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