Question

use each of the terms below just once to complete the statements. counting numbers, estimated, non - zero, zeros, scientific notation, significant figures, placeholders. 25. the digits that are reported in an answer are called. 26. the numeral 9.66 has three significant figures, two known figures and one figure. 27. numbers are always significant. 28. all final to the right of another number are significant if the number has a decimal point. 29. zeros that act as are not significant. 30. have an infinite number of significant figures. 31. when you convert to, you remove the placeholder zeros. significant figures. 32. round the following to four significant figures. a. 12.555 km, b. 1.0009 ml, c. 99.999 g, d. 23.342999 m. 33. round 120.752416 g to the requested number of significant figures. a. 3 significant figures, b. 4 significant figures, c. 5 significant figures, d. 7 significant figures

Explanation:

1. By definition, the digits reported in an answer are significant figures.
2. In a measurement with significant - figures, the last digit is an estimated value.
3. Non - zero numbers are always significant in significant figure rules.
4. Final zeros to the right of a number with a decimal point are significant.
5. Zeros that are just placeholders (e.g., in a number like 100 where the zeros just show the magnitude) are not significant.
6. Counting numbers, like counting the number of objects in a set, have an infinite number of significant figures as they are exact values.
7. Scientific notation removes placeholder zeros to clearly show significant figures.

32.

• a. For 12.555 km, when rounding to four significant figures, we look at the fifth digit. Since 5 is equal to 5, we round up the fourth digit. So it is 12.56 km.
• b. For 1.0009 ml, it already has five significant figures. Rounding to four significant figures, we look at the fifth digit (9). Since 9>5, we round up the fourth digit. So it is 1.001 ml.
• c. For 99.999 g, rounding to four significant figures, we look at the fifth digit (9). Since 9>5, we round up the fourth digit. So it is 100.0 g.
• d. For 23.342999 m, rounding to four significant figures, we look at the fifth digit (2). Since 2<5, we keep the fourth digit as it is. So it is 23.34 m.

33.

• a. For 120.752416 g rounding to 3 significant figures, we look at the fourth digit (7). Since 7>5, we round up the third digit. So it is 121 g.
• b. For 120.752416 g rounding to 4 significant figures, we look at the fifth digit (5). Since 5 = 5, we round up the fourth digit. So it is 120.8 g.
• c. For 120.752416 g rounding to 5 significant figures, we look at the sixth digit (2). Since 2<5, we keep the fifth digit as it is. So it is 120.75 g.
• d. For 120.752416 g rounding to 7 significant figures, we look at the eighth digit (6). Since 6>5, we round up the seventh digit. So it is 120.7524 g.

Answer:

1. Significant figures
2. Estimated
3. Non - zero
4. Zeros
5. Placeholders
6. Counting numbers
7. Scientific notation
8. a. 12.56 km, b. 1.001 ml, c. 100.0 g, d. 23.34 m
9. a. 121 g, b. 120.8 g, c. 120.75 g, d. 120.7524 g