Chapter 1: Significant Figures and Dimensional Analysis

Question 1

What is the formula for calculating density?

Answer 1

mass/volume

Question 2

What are exact numbers?

Answer 2

values that are exactly known and you can count the number
ex: 1 kg = 1000 g, 1 inch = 2.54 cm

Question 3

What are inexact numbers?

Answer 3

values that are uncertain and you can’t really count to find the exact number
ex: mass of a dime, length of a building

Question 4

How is error in scientific measurements reflected?

Answer 4

• the number of figures reported for measurement (higher uncertainty with less figures)
• when two successive measurements are different
• error in equipment

Question 5

Accuracy

Answer 5

measurements are close to the “correct” value

Question 6

Precision

Answer 6

measurements are close together

Question 7

What does the number of digits say about accuracy and precision?

Answer 7

The number of digits reflects the accuracy of the measurement and the precision of the measuring device

Question 8

What are significant figures?

Answer 8

all figures known with certainty plus one extra figure

Question 9

How are results reported in a multiplication or division calculation?

Answer 9

reported to fewest significant figures

Question 10

How are results reported in an addition/subtraction calculation?

Answer 10

reported to fewest decimal places

Question 11

What are the rules of significant figures?

Answer 11

1. All nonzero numbers are significant.
2. Zeros between nonzero digits are always significant.
3. Zeros at the beginning of a number are never significant.
4. Zeros at the end of a number are always significant if they come after a decimal point.
5. When a number with no decimal has zeros at the end, the zeros are not significant.