Section 2.3
How reliable are measurements?
Practice Test
1.
Why are plus and minus signs ignored in calculating percent error?
a.
Accepted values for data do not include negative numbers.
b.
An experimental value smaller than the accepted value is not considered an error.
c.
Only the size of the error matters, not whether the values in error are larger or smaller than the accepted values.
d.
The formula for percent error automatically cancels out the signs.
Hint
2.
Which of the following numbers has 4 significant figures?
a.
0.05208
b.
0.052
c.
0.0521
d.
0.52089
Hint
3.
The sum of 4.824 + 2.03 + 4.72319 + 123.4567 + 111.1 expressed to the proper number of significant figures is ____________.
a.
246
b.
246.1
c.
246.13
d.
246.134
Hint
4.
Perform the indicated mathematical operations and report the answer to the proper number of significant figures. (21.55 x 4.12 ) / 42.42
a.
2.1
b.
2.09
c.
2.093
d.
2.093 0
Hint
5.
The closeness of an experimental value to an accepted value is its ______.
a.
accuracy
b.
precision
c.
percent error
d.
error
Hint
6.
A measure of the closeness of a series of measurements is their ___________ .
a.
accuracy
b.
precision
c.
percent error
d.
error
Hint
7.
What is the percent error if a measured value is 24.59 g/mL and the accepted value is 25.49 g/mL?
a.
0.9647
b.
1.037
c.
0.0366
d.
3.5%
Hint
8.
Which of the following is not a significant figure?
a.
a value of 1 through 9
b.
a zero between two digits that have values of 1 through 9
c.
zeros to the right of a significant digit when a decimal point is present
d.
zeros to the left of the first significant digit
Hint
9.
How many significant figures will there be when the density value is calculated from the following data? mass = 24.47g; volume =13.2 mL
a.
2
b.
3
c.
4
d.
5
Hint
