Question

name: troy peace class: 4 even date: 9/8/25 test 1.2 and 2.3 general chemistry multiple choice identify the choice that best completes the statement or answers the question. 1. the base unit for mass is the a. cubic centimeter. b. gram. c. meter. d. kilogram. 2. the si base unit for time is the a. second. b. day. c. hour. d. minute. 3. the weight of an object a. depends on its location b. is the same as its mass c. is not affected by gravity d. is always the same 4. when determining the number of significant digits in a measurement, a. all zeros between two nonzero digits are not significant. b. all zeros are significant. c. all nonzero digits are not significant. d. all nonzero digits are significant. 5. in the measurement 0.503 l, which digit is the estimated digit? a. the 0 immediately to the left of the 3 b. 3 c. 5 d. the 0 to the left of the decimal point 6. which of the following measurements is expressed to three significant figures? a. 7.30×10⁻⁷ km b. 7077 mg c. 0.070 mm d. 0.007 m 7. which of the following measurements contains two significant figures? a. 0.00400 l b. 0.00044 l c. 0.00440 l d. 0.00404 l 8. the measurement that has been expressed to four significant figures is a. 402.10 mm. b. 0.0020 mm. c. 30.00 mm. d. 0.000402 mm. 9. what is the number 4.28×10⁴ in standard notation? a. 4,280,000 b. 42,800 c. 428 d. 0.000428 10. what is the number 0.000 000 920 expressed in scientific notation? a. 9.2×10⁻⁷ b. 9.2×10⁻⁶ c. 9.2×10⁶ d. 9.2×10⁷ short answer 11. how many significant figures are in the measurement 40,500 mg? 12. how many significant figures are in the measurement 811.40 grams?

Explanation:

1. The base - unit for mass in the SI system is the kilogram.
2. The SI base - unit for time is the second.
3. The weight of an object depends on its location as it is related to the gravitational force acting on it.
4. In a measurement, all nonzero digits are significant.
5. In 0.503 L, the estimated digit is the last digit, which is 3.
6. For scientific notation, the coefficient determines the number of significant figures. 7.30×10⁻⁷ km has three significant figures.
7. 0.00400 L has two significant figures as leading zeros are not significant but trailing zeros after a decimal point are significant.
8. 402.10 mm has five significant figures, 0.0020 mm has two significant figures, 30.00 mm has four significant figures, 0.000402 mm has three significant figures.
9. 4.28×10⁴ in standard notation is 42800.
10. 0.000000920 in scientific notation is 9.2×10⁻⁷.
11. In 40,500 mg, the trailing zeros may or may not be significant. Assuming they are not significant (without further context), there are three significant figures.
12. In 811.40 grams, all digits are significant, so there are five significant figures.

Answer:

1. d. kilogram
2. a. second
3. a. depends on its location
4. d. all nonzero digits are significant
5. b. 3
6. a. 7.30×10⁻⁷ km
7. a. 0.00400 L
8. c. 30.00 mm
9. b. 42,800
10. a. 9.2×10⁻⁷
11. 3
12. 5