1. Density

2. What is Density? Density is a characteristic physical property of matter -Each substance has its own density and many substances can be identified by their densities

3. Densities of Some Substances In this picture: What is the most dense substance? What is the least dense? What 2 substances have really close densities?

4. What is Density? a measure of how closely packed the particles are in a substance the amount of matter a substance has in a certain space (how much mass is contained per unit of volume of a substance) A substance with a low density feels “light” and will float in a substance with a higher density. A substance with a high density feels “heavy” and will sink in a substance with a lower density.

5. The equation for density is: Density (D) = Mass (m) Volume (V) D= m V Density as an Equation

6. Solving Equations Use GUESS method: G-given (state what you are given in the question) U-unknown (state what you are trying to find) E-equation (write the equation and sub numbers in) S-substitute and solve (calculate your answer) S-statement (write out your answer in a full sentence) Must use this method for full marks!!!!

7. Calculate the density of a material that has a mass of 52.547 g and a volume of 13.51 cm 3. D= m V D = ? m = 52.547 g V = 13.51 cm 3 Therefore, the density of the material is 3.89 g/cm 3. = 52.547 g 13.51 cm 3 = 3.89 g/cm 3

8. The density of silver is 10.49 g/cm 3. If a sample of pure silver has a volume of 12.993 cm 3, what would be the mass? m = ? D = 10.49 g/cm 3 V = 12.993 cm 3 m= D x V = 10.49 g/cm 3 x 12.993 cm 3 = 136.2966 g = 136.30 g The mass of the sample would be 136.30 g

9. Pure gold has a density of 19.32 g/cm 3. How large would a piece of gold be if it has a mass of 318.93g? V = ? D = 19.32 g/cm 3 m = 318.93 g V = m D = 318.93 g 19.32 g/cm 3 = 16.508 cm 3 = 16.51cm 3 Therefore, the volume of gold would be 16.51 cm 3.

10. Practice Problems 1) What is the density of a substance with a volume of 30 cm 3 and a mass of 14 g? Answer: 0.47 g/cm 3 2) What is the mass of a substance with a density of 1.12 g/cm 3 and a volume of 15 mL? Answer: 17 g 3) What is the volume of a substance with a density of 0.78 g/cm 3 and a mass of 15 g? Answer: 19 cm 3

11. How can you measure Volume? 3 ways to measure Volume: 1) Use a ruler to measure (for regular shaped solids) and the equation V = l x w x h 2) Using a graduated cylinder (for liquids) 3) Displacement using a graduated cylinder (for irregular solids) using chart below : Trial Initial Volume (mL) Final Volume (mL) Volume of Unknown (mL) Unknown irregular shaped object 1 2 Average volume

12. How can you measure Mass? For solids: -use an electronic balance For liquids For liquids: - use an electronic balance to mass a graduated cylinder with and without the liquid, then subtract

13. Lab Activity Determine the identity of Unknown Materials (2 liquids and 2 solids) - see lab sheet Good Luck!