CHEM 1305- Home-work 1
NAME:
1) A tentative model or picture that offers an explanation for a scientific law is called a ________.
A) theory
B) hypothesis
C) fact
D) observation
2) A theory is ________.
A) a law that is yet to be tested and validated
B) a law that has been “approved” by at least 3 international scientific organizations
C) a hypothesis that has been tested and validated over a long period of time
D) a hypothesis which is yet to be tested and validated
3) Which of the following statements is incorrectly classified as a fact, a scientific law, or a hypothesis?
Statement
Classification
A)
All samples of gaseous substances expand when heated.
scientific law
B)
Magnesium metal ignites when heated to high temperatures.
fact
C)
Gasoline is insoluble in water.
scientific law
D)
Women live longer than men because they deal better with stress.
hypothesis
4)
The vastness of the volume of chemical information about our world requires that chemistry be
divided into subdisciplines. Match area of study to its subdiscipline of chemistry by placing the appropriate
letter in each blank space provided.
5)
Subdiscipline of chemistry
Area of study
1)
____
analytical
a)
2)
____
general
b) noncarbon-containing compounds
3)
____
organic
c)
4)
____
physical
d) carbon-containing compounds
5)
____
inorganic
e)
energy changes
analysis
fundamental laws and concepts
Indicate whether each of the following statements represents quantitative data or qualitative data.
A) A beaker containing calcium carbonate weighs 96.543 grams. ________
B) The gas in the container was reddish-brown in color. ________
C) The volume of a container of gas decreases as the pressure in the container increases. ________
D) A strip of magnesium ribbon is 1.24 centimeters in length. ________
6)
Which of the following contain three significant figures, and no others?
I. 326.0
II. 0.00310
A) II, III and V
7)
III. 46,900
B) II and III
IV. 1.070
C) IV and V
V. 0.020
D) I, III and IV
E) II and V
Which statement contains an exact number?
A) A gross of paper contains 144 sheets.
B) One sheet of paper is 0.0042 inches thick.
C) One sheet of paper measures 8.5  11 inches.
D) A ream of medium weight paper weighs 20 pounds
8)
Which measurement is consistent with a graduated cylinder which has an uncertainty of 0.1 mL?
A) 21.14 mL
B) 21 mL
C) 21.1 mL
D) 21.140 mL
E) 21.1400 mL
9)
Which measuring device below is the most accurate for measuring volume?
A) a beaker calibrated in 1 milliliter units
B) a graduated cylinder calibrated in 0.5 milliliter units
C) a graduated pipet calibrated in units of 0.1 milliliter
D) a buret calibrated in units of 0.02 milliliter
10) Which one of the following numbers contains 4 significant figures?
A) 6.43
B) 39.4
C) 0.0257
D) 92008
E) 3.090
11) In which one of the following numbers are none of the zeros significant?
A) 298.010
B) 3100
C) 0.00001470
D) 2.70400
E) 19.840
12) The calculator answer obtained from multiplying 21.08  1.9634 is 41.388472. The answer to the
correct number of significant figures is ________.
A) 41.388
B) 41.4
C) 41.39
D) 41.3884
E) 41
13) The correct answer obtained from subtracting 1.2 from 123.96 contains ________.
A) 2 significant figures
B) 3 significant figures
D) 5 significant figures
E) 1 significant figure
C) 4 significant figures
14) Which of the following statements is true?
1. 0.0206
2. 81.30
3. 29007
4. 123,000
5. 906.0
6. 300
A) Numbers that contain three significant figures are 1, 3, and 6.
B) Numbers in which all zeros are significant are 2, 3, 4, and 5.
C) Numbers in which none of the zeros are significant are 1 and 2.
D) Number with one significant figure is 6.
15) The number 3009.1 expressed in scientific notation to the correct number of significant figures
becomes
________.
A) 3.01  103
B) 3.009  104
D) 3.0091  103
E) 3.0091  103
C) 3.009  103
16) Perform the following mathematical operations. Express your answer to the proper number of
significant figures.
(93.789  5.40)  18.057 
A) 1600
B) 1590
C) 1596.2
D) 1596
E) 1596.239
17) The number 12.68  10 , when expressed in correct scientific notation, becomes ________.
2
A) 1268  104
B) 0.1268  100
C) 1.268  103
D) 1.268  103
Round off each of the following numbers to 3 significant figures.
18)
397.48
19)
20)
145,120
256,542,125
________
________
________
E) 0.1268  104