Chapter 2 Section 3 Using Scientific Measurements

Question 1

99.099g + 1.91g =

Answer 1

101.01g

Question 2

15.15cm x 2.10cm =

Answer 2

31.8cm²

Question 3

0.516g/ 1.0301g/cm³ =

Answer 3

0.501cm³

Question 4

1.05 x 10^-3cm / 6.135s =

Answer 4

1.71 x 10^-4cm/s

Question 5

21L - 13.8L =

Answer 5

7L

Question 6

(1.285 x 10^-2g) + (1.24 x 10^-3g) + (1.879 x 10^-1g) =

Hint: Convert to standard notation first

Answer 6

0.2020g

Question 7

8.40ft x 2.688ft =

Answer 7

22.6ft²

Question 8

1.367s - 1.34s =

Answer 8

0.03s

Question 9

203in x 940in =

Answer 9

190,000in²

Question 10

(6.2 x 10^-19g) / (1.6726217 x 10^-30g/proton)

Answer 10

3.7 x 10¹¹ protons

Question 11

A student experimentally determines the melting point of naphthalene to be 79.2°C. If the accepted value for the melting point of this compound is 80.3°C, what is the percent error in the experimental measurement?

Answer 11

Question 12

Express 16,000,000,000 in scientific notation.

Answer 12

1.6 x 10¹⁰

Question 13

Express 0.000 000 790 in scientific notation.

Answer 13

7.90 x 10^-7

Question 14

Express 12.0 in scientific notation.

Answer 14

1.20 x 10¹

Question 15

Express 0.000 752 in scientific notation.

Answer 15

7.52 x 10^-4

Question 16

How many significant figures are there in the measurement 1,582m?

Answer 16

4

Question 17

How many significant figures are there in the measurement 87,002g?

Answer 17

5

Question 18

How many significant figures are there in the measurement 0.0090m?

Answer 18

2

Question 19

How many significant figures are there in the measurement 70mL?

Answer 19

1

Question 20

How many significant figures are there in the measurement 3,000.°C?

Answer 20

4 (The decimal point makes all the zeros trailing the 3 significant)

Question 21

Five successive measurements of the mass of a sample of iron are shown below:

1. 251g
2. 324g
3. 549g
4. 004g
5. 615g

If the actual mass is 7.000g, describe the accuracy and precision of these measurements.

Answer 21

The measurements are not accurate because they are not close to the actual mass. The measurements are not precise because they are not close to each other.

Question 22

Which of the following would be the best way to report the volume of water found in the pictured graduated cylinder?

A. 6.6mL

B. 6.5mL

C. 6.60mL

D. 6.70mL

Answer 22

The correct answer is C. Remember the last digit of any measurement is the estimation digit. Estimate one digit beyond what is shown on the scale.

Question 23

How many pain units is the patient reporting?

Answer 23

73 units. The scale is marked at every ten units, so estimate to the nearest ones place.

Question 24

How many pain units is this patient reporting?

Answer 24

3.9 units. This scale is marked at every one pain unit; we can estimate to the nearest tenth of a unit.