1. Describe the four phases of matter. Compare their external, observable properties. Compare the nature of the forces between atoms or molecules (or both) in the solid, liquid, and gas phases.

3. What is the difference between a mixture of two elements and a compound formed from the two elements?

5. Why can gases be compressed so much more readily than solids or liquids?

7. Use the concept of pressure to explain why snowshoes are better than regular shoes for walking in deep snow.

11. Explain the difference between gauge pressure and absolute pressure.

13. The mass density of a mixture of ethyl alcohol and water is 950 kg/m3. Is the mixture mostly water, mostly alcohol, or about half and half? What is your reasoning?

15. Would the weight density of water be different on the Moon than it is on Earth? What about the mass density? Explain.

17. Workers are to install a hatch (door) near the bottom of an empty storage tank. In choosing how strong to make the hatch, does it matter how tall the tank is? How wide it is? Whether it is going to hold water or mercury? Explain.