Name: ANSWER KEY

Chapter 1 & 3 Science Methods Review

1.In order for something to contain matter, is must have mass and take up space.

2.Define the following:

Density-
Weight-
Mass-
Hypothesis-
Theory-
Law- / Mass divided by volume; often expressed in g/cm3
A measure of Earth’s gravitational pull on matter
A measure of the quantity of matter
A testable statement used for making predictions and carrying out experiments
A generalization that explains a body of known facts or phenomena
A description of an observed phenomenon

3.List the SI units for mass, length and temperature.

Mass: Kilogram
Length: meter / Temperature: Kelvin

4.What is the boiling point of water in degrees Celsius?

100°C / (373 K)

5.Sodium boils at 897 degrees C. What is the boiling point of Sodium expressed in Kelvins?

897 + 273 = 1170 K

6.The density of copper is 8.92 g/mL. The volume of a solid piece of copper is 2.50 mL. Find its mass.

22.3 g

7.The density of iron is 7.87 g/cm3. A sample of iron has a mass of 3.40 g. Find its volume.

0.432 cm3

8.The known mass of a certain product is 6.10 g. But during the lab, you obtained values of 6.95 g, 6.93 g and

6.97 g. Are your values accurate, precise, both or neither?

Precise

9.Using a metric ruler with 1 mm divisions, you find the sides of a rectangular piece of plywood are 2.54 cm and 8.62 cm. You calculate that the area is 21.8948 cm2. To the correct number of significant figures, the result should be expressed as ______.

21.9 cm2

10.Three samples of 0.12 g, 8.1 g, and 0.265 g are mixed together. The sum of the mass of all three samples, expressed to the correct number of significant figures, should be recorded as ______.

8.5 g

11.The quotient of 12 cm and 6.00 cm is correctly reported as (use significant figures): 2.0 cm .

12.Expressed in scientific notation, 0.008700 m is: 8.700 x 10-3m.

13.To two significant figures, the measurement 0.0376 g should be reported as: 0.038 g.

14.How is the distance 345 000 km, expressed in scientific notation?

3.45 x 105 Km

15.The number of significant figures in the measurement 0.000802 kg is 3 .

16.How many significant figures are in the measurement 186,000 mg?

3

17.What is the measurement 333.009 mm rounded off to four significant digits?

333.0 mm

18.In the measurement 0.427 L, which digit is the estimated digit?

7

19.If a man weighs 95 kg, how many pounds does he weigh?

1 L = 1.1 qt 1 ft = 12 in 1 kg = 1000 g 1 in = 2.54 cm 1 lbs = 454 g 1 L = 1000 mL

210 lbs

20.If you were to describe the flashlight you used during the Bright Idea activity, list two quantitative observations and two qualitative observations.

Quantitative- It contained 2 batteries. It had 1 switch. It contained 1 light bulb.

Qualitative- It had ridges on the outside. It was blue and white. The bulb was burned out.

21.Describe how you could determine the volume of a chunk of magnesium.

1. Measure out a known amount of water, ex. 20 mL, in a graduated cylinder.

2. Add the chunk of magnesium to the graduated cylinder.

3. Measure the water level.

4. Subtract the initial amount of water from the final amount of water.

22.Once you determine the volume of the magnesium and then obtain the mass, how can you calculate the density?

Divide the mass by the volume. This also enables you to double-check that the chunk is indeed magnesium.