Day 32

This class period will be asynchonous. You don't have to join a discussion today. The homework is due at the end of our normal class period: 12:15. It is Class Review Homework Set #5, a quiz on Canvas.

1. The water molecule has one oxygen and two hydrogen atoms. Why do these atoms stay together?

2. Compare a polar molecule with a nonpolar molecule. Describe what a model of each would look like.

3. Identify each of the following as ionic, polar, or nonpolar: (a) HCl, (b) N2, (c) SiO, (d) BaO, (e) LiBr.

4. Why does water and oil separate after vigorous shaking?

5. (a) Two materials have the same molecular mass, but one evaporates faster than the other. Explain. (b) Two materials have the same polarity, but one evaporates faster than the other. Explain.

6. Solid Crisco shortening and liquid Wesson Oil are both fats used for cooking. Why is Crisco a solid and Wesson Oil a liquid at room temperature? Use what we have learned in class to fully answer this question.

7. We saw that water in a test tube actually can form a "dome" with the water higher than the top of the test tube. Some people say this is due to "surface tension". How do we explain this surface tension? What science concept do you need to know in order to correctly explain surface tension?

8. When water is placed in a glass tube a meniscus is formed where the water is higher next to the glass than it is at the center. Explain this observation.