Chemistry

c. 6.022 x 1023 atoms (number of carbon atoms in 12.01 g of carbon)

d. 4.5 x 10 – 7 m (wavelength of blue light)

2. Why are the number of digits reported in scientific measurements important?

3. What can you do as a scientist to increase the precision of measurements made in an experiment?

4. When do zeros count as significant figures and when don’t they count?

5. How many significant figures are in each measurement?

a.

b. 100,000 L

c. 100.00 L

d. 100. L

e. 100 L

f. 0.001 L

g. 0.100 L

h. 1 x 103 L

i. 1.000 x 103 L

6.

7. Perform each calculation to the correct number of significant figures.

a. 1.10 x 0.512 x 1.301 x 0.005 ÷ 3.4

b. 7.876 – 0.56 + 123.792

c. 3.897 x (782.3 – 451.88)

d. (4.58 ÷ 1.239) – 0.578

e. (1.7 x 106 ÷ 2.63 x 105) + 7.33

8. Which calculation would have its result reported to a greater number of significant figures? Multiple choice; choose one answer. Explain your reasoning.

a.

b. 3 + (15/12)

c. (3 + 15)/12

9.

10. A liquid sample has a reported volume of 810 mL.

a. What is the implied +/- error of this measurement?

b. Identify the certain and the uncertain digits in the measurement.

c. If the volume was instead reported as 810. mL, what would be the implied +/- error? And, identify the certain and uncertain digits.

d. Which of the two volumes 810 mL or 810. mL is more precise?

11. Draw a Celsius thermometer that is capable of producing a recorded measurement of 48.50 °C.

12. Round the number on the left to the number of significant figures indicated in each column. Use scientific notation as needed to avoid ambiguity.