CHE 105/110 Introduction to Chemistry - Exercises and Answers

1.

Express each measurement to the correct number of significant figures.

1.

1. 375 psi
2. 1.30 cm

3.

How many significant figures do these numbers have?

1. 23
2. 23.0
3. 0.00023
4. 0.0002302

3.

1. two
2. three
3. two
4. four

5.

How many significant figures do these numbers have?

1. 765,890
2. 765,890.0
3. 1.2000 × 10⁵
4. 0.0005060

5.

1. five
2. seven
3. five
4. four

7.

Compute and express each answer with the proper number of significant figures, rounding as necessary.

1. 56.0 + 3.44 = ?
2. 0.00665 + 1.004 = ?
3. 45.99 − 32.8 = ?
4. 45.99 − 32.8 + 75.02 = ?

7.

1. 59.4
2. 1.011
3. 13.2
4. 88.2

9.

Compute and express each answer with the proper number of significant figures, rounding as necessary.

1. 56.7 × 66.99 = ?
2. 1.000 ÷ 77 = ?
3. 1.000 ÷ 77.0 = ?
4. 6.022 × 1.89 = ?

9.

1. 3.80 × 10³
2. 0.013
3. 0.0130
4. 11.4

11.

1. Write the number 87,449 in scientific notation with four significant figures.
2. Write the number 0.000066600 in scientific notation with five significant figures.

11.

1. 8.745 × 10⁴
2. 6.6600 × 10⁻⁵

13.

13.

1. 293
2. 53.3