Chapters 1 & 2

1. A scientist who is trying to make an insecticide that is more toxic to mosquitoes than to

humans would be involved in what?

a. basic research b. applied research c. technology d. serendipity

b. Applied Research

2. Identify each of the following outdoor activities as a physical or chemical change?

  1. Raking leaves- Physical
  2. Burning leaves- Chemical
  3. Starting a lawn mower-Chemical
  4. Mowing the lawn-Physical
  5. Digging a garden-Physical
  6. Growing a garden-Both Chemical and Physical

3. Is it possible that scientists in other branches of biological and physical sciences might

also study DNA? If so, explain what they might be looking for.

Yes, There are many possibilities, i.e. studying the transition chemistry of cis to trans conformation of a base using femto-second spectroscopy to monitor the life-time and decay.

4. Name two elements that are solids, two that liquids, and two that are gases.

Solids: gold and iron

Liquids: mercury and bromine

Gases: hydrogen and oxygen

5. Write the symbols for the six elements you named in question 4.

Au, Fe

Hg, Br

H, O

6. Name four kinds of energy. (See Chapter 2, Table 2.1)

Electric

Heat

Light

Mechanical

7. Is it possible to have a mixture of two elements and also to have a compound of the

same two elements? Explain. Can you think of an example?

Yes, H2 and O2 and H2O

8. Is the tea in tea bags a pure substance? Use the process of making tea to make an

argument for your answer. How would your argument apply to instant tea?

The tea in a tea bag is a mixture. Instant tea is composed of the water soluble substances in tea which when dissolved in water would be a homogeneous mixture.

9. a. How many milligrams are there in 1 gram?

1000

b. How many meters are there in 1 kilometer?

1000

c. How many centigrams are there in 1 gram?

100

10. Which of the following quantities is a density? (hint check your units!)

  1. 9 cal/g
  2. 100 cm/m
  3. 1.5 g/ml
  4. 454 g/lb

11. A computer has 60 gigabyte hard drive. How many bytes is this?

60 gigabytes x 1 X 109 bytes/ 1 gigabyte = 6.0 x 109 bytes

12. Complete the following:

  1. 4 cm x 1 m/100 cm = 0.04 m
  2. 328 mL x 1 L/1000 mL = 0.328 L
  3. 0.98 kg X 1000 g/1 kg = 980 g
  4. 0.043 g x 1000 mg/1 g = 43 mg