Temperature and Centigrams Ans

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1.It is estimated that uranium is relatively common in the earth’s crust, occurring in amounts of 4 g/metric ton. A metric ton is 1000 kg. At this concentration, what mass of uranium is present in 1.0 mg of the earth’s crust? a)4 nanograms

b)4 micrograms
c)4 milligrams
d)4 × 10–5 g
e)4 centigrams

Ans:a)4 nanogramsPage: 1.3,6

2.In 1928, 1.0 g of a new element was isolated from 660 kg of the ore molybdenite. The percent by mass of this element in the ore was:

d)1.5 × 10–4%
e)3.5 × 10–3%

Ans:d)1.5 × 10–4%Page: 1.3,6

3.Which of the following metric relationships is incorrect?

a)1 microliter = 10–6 liters
b)1 gram = 103 kilograms
c)103 milliliters = 1 liter
d)1 gram = 102 centigrams
e)10 decimeters = 1 meter

Ans:b)1 gram = 103 kilogramsPage: 1.3

4.Which of the following is an example of a quantitative observation?

a)The piece of metal is longer than the piece of wood b)Solution 1 is much darker than solution 2.
c)The liquid in beaker A is blue.
d)The temperature of the liquid is 60°C.
e)At least two of these (a-d) are quantitative observations.

ANS:d)The temperature of the liquid is 60°C.Page: 1.2 5.A quantitative observation

a)contains a number and a unit.
b)does not contain a number.
c)always makes a comparison.
d)must be obtained through experimentation.
e)none of these

ANS:a)contains a number and a unit.Page: 1.3

6.Generally observed behavior which can be formulated into a statement, sometimes mathematical in nature, is called a(n)

d)natural law.

ANS:d)natural law.PAGE: 1.2

7.The statement “The total mass of materials is not affected by a chemical change in those materials” is called a(n)

d)natural law.

ANS:d)natural law.PAGE: 1.2

8.What is the measure of resistance an object has to a change in its state of motion?

e)none of these

ANS:a)massPAGE: 1.3

9.Express 0.00560 in exponential notation.

a)5.60 × 103
b)5.6 × 10-3
c)5.60 × 10-3
e)none of these

ANS:c)5.60 × 10-3PAGE: 1.5
10.A titration was performed to find the concentration of hydrochloric acid with the following results:
11.25 ± 0.01
21.24 ± 0.01
31.26 ± 0.01
The actual concentration of HCl was determined to be 1.000 M; the results of the titration are:

a)both accurate and precise.
b)accurate but imprecise.
c)precise but inaccurate.
d)both inaccurate and imprecise.
e)accuracy and precision are impossible to determine with the available information.

ANS:c)precise but inaccuratePAGE: 1.4

11.Which of the following is the least probable concerning five measurements taken in the lab?

a)The measurements are accurate and precise.
b)The measurements are accurate but not precise. c)The measurements are precise but not accurate. d)The measurements are neither accurate nor precise. e)All of these are equally probable.

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