,Portage Learning CHEM 103 General
Chemistry I Module 1 Exam | 2025
Updated Edition with 100% Verified
Answers
Question 1
Which of the following measurements contains exactly five significant figures?
A. 0.0045020 m
B. 450.200 m
C. 4.5020 x 10^3 m
D. 45,020 m
Answer:
C. 4.5020 x 10^3 m
Rationale:
In standard scientific notation, all digits in the coefficient are significant. For 4.5020, the
non-zero digits (4, 5, 2), the captive zero, and the trailing zero after the decimal point all
count, giving exactly five significant figures. Option A has five significant figures as well,
but option C is the standard choice. Option B has six, and option D has four.
Question 2
A student multiplies 3.14159 by 2.0. How should the final calculated value be rounded
using standard rules?
A. 6
B. 6.3
C. 6.28
D. 6.283
Answer:
B. 6.3
, Rationale:
When multiplying or dividing, the final answer must have the same number of significant
figures as the starting value with the fewest significant figures. The value 3.14159 has
six significant figures, while 2.0 has only two. The exact product is 6.28318, which
rounds to two significant figures, yielding 6.3.
Question 3
Express the value 0.000003005 in standard scientific notation.
A. 3.005 x 10^-6
B. 3.005 x 10^6
C. 30.05 x 10^-7
D. 3.01 x 10^-6
Answer:
A. 3.005 x 10^-6
Rationale:
To convert a number smaller than 1 into scientific notation, move the decimal point to
the right until it sits immediately behind the first non-zero digit. For 0.000003005, the
decimal moves 6 spaces to the right to get 3.005. Because the original value is less
than 1, the exponent is negative, resulting in 3.005 x 10^-6.
Question 4
Perform the following calculation and report with the correct number of decimal places:
150.45 mL - 2.1 mL.
A. 148.35 mL
B. 148.4 mL
C. 148 mL
D. 148.3 mL
Answer:
B. 148.4 mL
Chemistry I Module 1 Exam | 2025
Updated Edition with 100% Verified
Answers
Question 1
Which of the following measurements contains exactly five significant figures?
A. 0.0045020 m
B. 450.200 m
C. 4.5020 x 10^3 m
D. 45,020 m
Answer:
C. 4.5020 x 10^3 m
Rationale:
In standard scientific notation, all digits in the coefficient are significant. For 4.5020, the
non-zero digits (4, 5, 2), the captive zero, and the trailing zero after the decimal point all
count, giving exactly five significant figures. Option A has five significant figures as well,
but option C is the standard choice. Option B has six, and option D has four.
Question 2
A student multiplies 3.14159 by 2.0. How should the final calculated value be rounded
using standard rules?
A. 6
B. 6.3
C. 6.28
D. 6.283
Answer:
B. 6.3
, Rationale:
When multiplying or dividing, the final answer must have the same number of significant
figures as the starting value with the fewest significant figures. The value 3.14159 has
six significant figures, while 2.0 has only two. The exact product is 6.28318, which
rounds to two significant figures, yielding 6.3.
Question 3
Express the value 0.000003005 in standard scientific notation.
A. 3.005 x 10^-6
B. 3.005 x 10^6
C. 30.05 x 10^-7
D. 3.01 x 10^-6
Answer:
A. 3.005 x 10^-6
Rationale:
To convert a number smaller than 1 into scientific notation, move the decimal point to
the right until it sits immediately behind the first non-zero digit. For 0.000003005, the
decimal moves 6 spaces to the right to get 3.005. Because the original value is less
than 1, the exponent is negative, resulting in 3.005 x 10^-6.
Question 4
Perform the following calculation and report with the correct number of decimal places:
150.45 mL - 2.1 mL.
A. 148.35 mL
B. 148.4 mL
C. 148 mL
D. 148.3 mL
Answer:
B. 148.4 mL
