# Solutions to Problems Give the number of significant figures in each Solutions to Problems Give the number of significant figures in each of the following:

3 3 2 7 4 2 2 3 1 3 5 2

Multiply each of the following, observing significant figure rules:

5500 m 2 7300 m 2 40 in 2 .038 in 2 5.1 m 2 3890000cm 2

Divide each of the following, observing significant figure rules:

47 m/s 3.8 mi/hr .437 g/mol 99 m/s

Add each of the following, observing significant figure rules:

3.0 m 106.89 g 111 cm

Subtract each of the following, observing significant figure rules:

41.09m 10.86 g 172.1 cm

Work each of the following problems, observing significant figure rules:

Average percent = 7.36% V = 320 cm 3 m = 46593.6 g = 46600 g m = 177000 g

Significant Figures Practice Part I:

1.

2.

3.

4.

5.

5 2 5 3 5

Part II:

6.

7.

8.

7.85 x 10 -3 1.007 x 10 3 1.53101 x 10 4 9.

3.5006700 x 10 7 10.

3.1700 x 10 -2

Part III:

11.

.00137 12.

2907000 13.

7500 14.

.00004301 15.

900.0

Part IV:

16.

139.3 mm 17.

217.2 g 18.

112.2 kg 19.

-129.04 m

Part V:

20.

173.2 mm 2 21.

.91 m 2 22.

13.3 m/s 23.

15 dollars/lb

Percent Error Practice Sheet

1.

2.

3.

4.

5.

6.

7.

16.6% = 17% 8/40% = 8% 11.1% = 10% 10.0% = 10% 15.4% = 15% 13.2% 16.5%

Density Practice Problems

1.

2.

D = 2.70 g/mL D = 13.6 g/mL 3.

4.

5.

6.

7.

8.

m = 158 g D = 8.9 g/cm 3 D = 1.59 g/mL D = 1.84 g/mL D = 220 g D = 11.3 g/cm 9.

D = 7.92 g/mL 10.

V = 238 cm 3 3

Practice Worksheet 1.

State the number of significant digits in each measurement

a.

b.

3 4

2.

c.

d.

4 3

Round the following numbers as indicated: To four figures:

a.

b.

3.682 21.86 c.

112.5

To one decimal place:

a.

b.

c.

2 6 8

To two decimal places: 3.

a.

b.

0.031 3.4 c.

42

Solve the following problems and report answers with appropriate number of significant digits:

a.

26.3 cm b.

c.

d.

e.

f.

g.

1614 m 0.5 g Cannot do 3.0 cm 2 2.73 cm/s 3.07708 g

4.

5.

6.

7.

8.

Express in scientific notation:

a.

1.238763 x 10 5 b.

c.

d.

1.236840 x 10 6 2.11 x10 -13 2.38 x 10 -4

Identify the sums or differences of the following:

a.

1.81 x 10 5 b.

c.

d.

9.1 x 10 1 1.2 x 10 4 4.2 x 10 -2

Express the product and the quotients of the following:

a.

1.50 x 10 12 b.

c.

d.

1.6 x 10 -1 1.25 x 10 4 8.2 x 10 3

Fill in the blanks:

a.

1,000,000 µg = 1 g b.

1,000,000 s = 1 Ms

Do the following conversions. Don’t forget significant figures!

a.

b.

c.

0.000347 g 6.724 x 10 1 mm 346800 g d.

14000 mL

Dimensional Analysis

5.

6.

44640 min = 45000 min 672 test tubes = 700 test tubes 7.

8.

\$19.74 4.500 x 10 6 km/min 9.

m = 21975 mg = 22000 mg 10.

2.6785 x 10 12 µs 11.

How many: a.

86400 s b.

c.

750000 mg .00075 g d.

12.

\$70.31 250000000 cm