1. WHAT IS DENSITY One of the most important physical properties of a substance is its density, or what is mass per unit volume. The property of density may be used to help identify a substance. Gold, for example, is much more dense (heavier) a substance than copper even though their colors may be similar. One of the most important physical properties of a substance is its density, or what is mass per unit volume. The property of density may be used to help identify a substance. Gold, for example, is much more dense (heavier) a substance than copper even though their colors may be similar.

2. Density is the mass in grams (g) for each milliliter (mL) or cubic centimeter (cm3) of a substance. Density is the mass in grams (g) for each milliliter (mL) or cubic centimeter (cm3) of a substance. This relationship may be expressed as follows: Density = Mass / Volume or This relationship may be expressed as follows: Density = Mass / Volume or D = M/V D = M/V

3. Question #1 What is the density of a solid whose mass is 19.57g and whose volume is 3.6mL? What is the density of a solid whose mass is 19.57g and whose volume is 3.6mL?

4. Answer D = mass / volume D = mass / volume D = 19.57g / 3.6mL D = 19.57g / 3.6mL D = 5.6g/mL D = 5.6g/mL

5. Question #2 An irregular solid has a mass of 12.77 grams. When the solid is lowered into a graduated cylinder filled with 10.0 mL of water, the water level rises to 13.1mL. What is the density of the solid? An irregular solid has a mass of 12.77 grams. When the solid is lowered into a graduated cylinder filled with 10.0 mL of water, the water level rises to 13.1mL. What is the density of the solid?

6. Answer Density = Mass / Volume Density = Mass / Volume Mass = 12.77g Mass = 12.77g Volume = 13.1mL – 10.0mL = 3.1mL Volume = 13.1mL – 10.0mL = 3.1mL D = 12.77g / 3.1mL D = 12.77g / 3.1mL D = 4.12 g /mL D = 4.12 g /mL

7. Question #3 The method used in this experiment would not be a satisfactory way to measure the volume of salt or sugar crystals. Why? The method used in this experiment would not be a satisfactory way to measure the volume of salt or sugar crystals. Why?

8. Question #4 What has a greater mass? A pound of lead or a pound of feathers. What has a greater mass? A pound of lead or a pound of feathers. What has a greater density? 100g of lead or 100 g feathers. What has a greater density? 100g of lead or 100 g feathers.

9. Density Comparison to Water In chemistry, the density of many substances is compared to the density of water. Does an object float on water or sink in the water? If an object such as a piece of wood floats on water it is less dense than water vs. if a rock sinks, it is more dense than water. In chemistry, the density of many substances is compared to the density of water. Does an object float on water or sink in the water? If an object such as a piece of wood floats on water it is less dense than water vs. if a rock sinks, it is more dense than water.

10. Densities of Common Elements and Compounds Substance Density (g/ml) Pine wood 0.35 – 0.50 Water1.00 Salt2.16 Aluminum2.70 Gold19.3 Mercury7.80 Iron13.5