CHEM 120 Homework
Chapter 1
1) Which
the following statement about scientific method is false
a) Scientific
method is a procedure followed by scientist around the world.
b) It usually starts with an experiment, looking for patterns in the data, hypotheses,
theory then further experiments.
c) Scientific
Theory will never become obsolete.
d) Patterns in
observations are summarized as a scientific law.
e) Further experiments confirm and sometimes modify or replace a theory.
2.
An
example of a chemical compound is,
a) air b) brass (an alloy) c) granite (a rock) d) table salt
3.
An
example of a physical change
a)
Bakinga cake b) Burning fire wood c) Electrolysis of water d) Sublimation of
dry ice.
4. Samples of seawater obtained from various
locations vary in the weight percentage of various elements present in the
sample. This suggests that seawater is
a.
mixture.
b. a compound. c. an element. d. a pure
substance.
5. Which
name/symbol combination is wrong?
a.
Tungstun/W b. Fluorine/F
c.Silicon/Si d. Selenium/Sn e. Silver/Ag
6. Compounds are different from mixtures
because compounds
a.
are composed of two or more substances.
b.
have compositions that may vary from substance to substance.
c.
always have the same set of physical properties.
d.
can be separated by physical means into simpler substances.
7. Which of the
following is a chemical property of iron?
a. occurs in an abundance of
4.7% in the earth's crust
b.
melts at 1535 oC
c.
attracted to a magnet
d.
rusts when exposed to moist air
8. Convert -78
oC to oF.
a.
-108 oF b. -61 oF
c. -195 oF d. -351 oF
9. The correct answer to report for
2.481 x 12.74 + 0.27 is
2.69
a.
12.0202 b.
12.020 c.
12.02 d.
12.0 e. 12
10. How many
cubic meters equal one cubic millimeter?
a.
109 b.
106 c.
10-2 d. 10-9