Chapter 3 Practice #2                                                              Name ____________________________________

1. Explain why the following statements are true, describing which numbers are significant, and which are not.

A. The measurement 90.7 g has three significant figures.

B. The measurement 0.0742 L has three significant figures.

C. The measurement 18200 m has three significant figures.

D. The measurement 18.200 seconds has five significant figures.

2. Write the number of significant figures in the following measurements.

_____ A.      2.708

_____ B.       50.007

_____ C.       0.00045

_____ D.      589000

_____ E.       50800

_____ F.        789.006

_____ G.      507.7800

_____ H.      0.00480

_____ I.         540300

_____ J.         287.345

_____ K.      16.3050

_____ L.       3000010

_____ M.     0.00458

_____ N.      6.38 x 109

_____ O.      4.678 x 1022

_____ P.        3.67 x 10-4

_____ Q.      0.000000875

_____ R.       3322.008

_____ S.        4506.003

_____ T.        56.000

_____ U.      30.230

3. Round 80.45 to

a)      3 significant figures                      b) 2 significant figures                        c) 1. significant figure

4. Round the following numbers to three significant figures

_____________ A.  50.63

_____________ B.   1823

_____________ C.   1.823 x 103

_____________ D.  08129

_____________ E.       .004536

_____________ F.        4.5636 x 10-3

_____________ G.      12.98

_____________ H.      13.02

_____________ I.     129.8

_____________ J.     1.2046

_____________ K.  120.46

_____________ L.   12.04

5. Matching: Match each description in Column B to the correct term in Column A.

Column A

_____ 1. accuracy

_____ 2. measurement

_____ 3. precision

_____ 4. scientific notation

_____ 5. experimental value

_____ 6. significant figures

Column B

a. measure of how close a series of measurements are to one another

b. measure of how close a measurement comes to the actual value

c. digits in a measurement that are known plus one that is estimated

d. a value determined in the laboratory e. a quantity that has both a number and a unit

f. a method of expressing numbers as a product of a coefficient and a power of 10.

6. Use your calculator to answer the following, using the correct significant figures

A. 2.345 + 6.487 =                                               F. 68.439 - 54.1 =

B. 2.7 x 104  + 3.67 x 104 =                                         G. 7.8 x 106  - 2.4 x 105 =

C.  8.4 x 10-4  + 6.89 x 10-4 =                                     H.  2.7 x 10-4  - 3.67 x 10-5 =

D. 456 x 21 =                                             I. 3200 x 460  =

E. J. 7. Use your calculator to answer the following. Write your answer in scientific notation.

 A. E. G. B. C. F. H. D. 8. Which of these rulers could have been used to measure the following distances?

 _____ A.      2.7 cm _____ B.       3 cm _____ C.       2.72 _____ D.      10.1 _____ E.       11.2 _____ F.        6.72 _____ G.      10.74 I. II. III.