1. End Show Slide 1 of 25 Density 3.4

2. End Show © Copyright Pearson Prentice Hall Slide 2 of 25 Density If you think that these lily pads float because they are lightweight, you are only partially correct. The ratio of the mass of an object to its volume can be used to determine whether an object floats or sinks in water. 3.4

3. End Show © Copyright Pearson Prentice Hall Density > Slide 3 of 25 Determining Density What determines the density of a substance? Density is an intensive property that depends only on the composition (the stuff it is made of) of a substance, not on the size of the sample. 3.4

4. End Show © Copyright Pearson Prentice Hall Slide 4 of 25 Density > Determining Density Density is the ratio of the mass of an object to its volume. 3.4

5. End Show © Copyright Pearson Prentice Hall Slide 5 of 25 Density > Determining Density Each of these 10-g samples has a different volume because the densities vary. 3.4

6. End Show © Copyright Pearson Prentice Hall Slide 6 of 25 Density > Determining Density Sample Densities 3.4

7. End Show © Copyright Pearson Prentice Hall Slide 7 of 25 Density > Determining Density The density of corn oil is less than the density of corn syrup. For that reason, the oil floats on top of the syrup. Water has a density of 1 g/cm3. If a substance is less dense than water, it floats. If a substance is more dense than water, it sinks. 3.4

8. End Show © Copyright Pearson Prentice Hall Density > Slide 8 of 25 Density and Temperature How does a change in temperature affect density? Experiments show that the volume of most substances increases as the temperature increases. Meanwhile, the mass remains the same. Thus, the density must change. The density of a substance generally decreases as its temperature increases. This is because the molecules move farther apart. 3.4

9. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 9 of 25 End Show 3.10

10. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 10 of 25 End Show What is the most dense substance in the picture? Why does the oil float on top of the water?

11. © Copyright Pearson Prentice Hall Slide 11 of 25 End Show Practice Problems for Sample Problem 3.10

12. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide 12 of 25 End Show 3.11

13. © Copyright Pearson Prentice Hall Slide 13 of 25 End Show 3.4 Section Quiz 1. If 50.0 mL of corn syrup have a mass of 68.7 g, the density of the corn syrup is a.0.737 g/mL. b.0.727 g/mL. c.1.36 g/mL. d.1.37 g/mL.

14. © Copyright Pearson Prentice Hall Slide 14 of 25 End Show 3.4 Section Quiz 2. What is the volume of a pure gold coin that has a mass of 38.6 g? The density of gold is 19.3 g/cm 3. a.0.500 cm 3 b.2.00 cm 3 c.38.6 cm 3 d.745 cm 3

15. © Copyright Pearson Prentice Hall Slide 15 of 25 End Show 3.4 Section Quiz 3. As the temperature increases, the density of most substances a.increases. b.decreases. c.remains the same. d.increases at first and then decreases.

16. END OF SHOW