Chemistry Unit 1 Practice Test
The Metric System and Scientific Method
No work shown = no credit. Please write legibly. Numerical answers must be rounded to the
appropriate number of significant figures or decimal points (honors only) and must contain the
appropriate unit (all classes).
1. Perform the following conversions. Each conversion is worth 2 points. (10 points)
(A) Convert 45.5 centimeters to meters. Show your work.
45.5 cm x
0.01 m
= 0.455 m
1 cm
(B) Convert 0.0931 grams to milligrams. Show your work.
1mg
= 93.1 g
0.001 g
0.0931 g x
(C) Convert 2.3x10-5 kilometers to centimeters. Show your work.
2.3x10-5 km x
1000 m
1 cm
x
= 2.3 cm
0.01 m
1km
(D) Convert 1100 microliters to milliliters. Show your work.
1100 L x
1 mL
0.000 001 L
x
= 1.1 mL
0.001
L
1μL
(E) Convert 9.0x103 seconds to hours. Show your work.
9.0x103 s x
1min
1hr
x
= 2.5 hr
60 s
60 min
2. Convert each of the following numbers from scientific notation to standard format and from
standard format to scientific notation. Each item is worth 1 point. (10 points)
(A) 4.78x10-3
0.004 78
(F) 469
4.69x102
(B) 7.3x104
73 000
(G) 0.00350
3.50x10-3
(C) 2.20x10-6
0.000 002 20
(H) 250 000
2.50x105
(D) 3x103
3 000
(I) 0.000 003 34
3.34x10-6
(E) 9.99x101
99.9
(J) 6
6x100
3. You are measuring the speed of light. The accepted value is 299 792 km/s. Your experimental
value is 289 144 km/s. What is your percent error? (10 points)
error = 289 144 km/s – 299 792 km/s = -10 648 km/s
%error =
 10 648 km/s
299 792 km/s
x 100% =
10 648 km/s
x 100% = 0.0355 x 100% = 3.55%
299 792 km/s
4. The accepted density of copper is 8.96 g/cm 3. Terry’s experimental value is 9.15 g/cm 3.
Calculate Terry’s percent error. (10 points)
error = 9.15 g/cm3 – 8.96 g/cm3 = 0.19 g/cm3
0.19 g/cm 3
% error =
8.96 g/cm 3
x 100% =
0.19 g/cm3
8.96 g/cm3
x 100% = 0.0212 x 100% = 2.12%
5. TRUE or FALSE: Theories can become laws when they are proven. (10 points)
FALSE. Theories and laws are different things. Theories never become laws and theories are
never 100% proven.
6. TRUE or FALSE: Scientists work alone and rarely share information. (10 points)
FALSE. Scientists usually work together, and sharing information is an important part of the
scientific method.
7. TRUE or FALSE: In science, theories explain a broad set of observations while laws describe
them. (10 points)
TRUE. A theory is a well-tested explanation for a broad set of observations. A law is a concise
statement that describes a relationship in nature.
8. Theo wants to know which brand of detergent is best for removing ketchup stains. He has picked
out five brands to test. He obtains six square pieces of white cotton cloth that are the same size.
He adds 1 oz of ketchup to each cloth and smears it in thoroughly, then allows the cloth samples
to sit for one week. For the first five squares he washes each square in a different brand of
detergent in hot water. He washes the sixth square in hot water without detergent. After the
washing he lays the squares side by side and compares the darkness of the ketchup stain left
behind.
(A) What is Theo’s manipulated (independent) variable? (5 points)
The brand of detergent he uses.
(B) What is Theo’s responding (dependent) variable? (5 points)
The darkness of the ketchup stain left behind.
(C) What is Theo’s control? (5 points)
The piece of cloth that receives no detergent.
(D) Why is it important that Theo used the same kind and color of cloth, the same water temperature,
etc? (5 points)
To be sure that none of those factors influences the dependent variable.
***The following questions apply to the honors version of the test only.***
9. Perform each of the following calculations, then report your answer with the correct number of
signficant figures and the proper units. Each item is worth 2.5 points. (10 points)
(A) 3.4 mL + 15.403 mL = 18.8 mL
(B) 0.392 g  0.029 cm3 = 14 g/cm3
(C) 153 cm – 22.9 cm = 130. cm
(D) 15.993 mm2 x 1.8 mm = 29 mm3