Matter and Energy
Chapter 2 Section Reviews
2-1 (pg 47 #1-10) 2-2 (pg 55 #1-11)
2-3 (pg 64 #1-12)
2-1 (pg 47 #1-10)
1.
What is the difference between
potential energy and kinetic energy?
Both are the capacity to do work.
Kinetic energy is the energy an
object has due to its motion.
Potential energy is the energy of an
object that has the potential to move
because of its position.
2-1 (pg 47 #1-10)
2.
What is the difference between
heat and temperature? Heat is
the total kinetic energy of the
particles in a sample of matter.
Temperature is a measure of the
average kinetic energy of the
particles in an object.
2-1 (pg 47 #1-10)
3.
Explain what the equation
E=mc2 signifies? The equation
represents the amount of energy
available when a quantity of
matter is changed completely
into energy.
2-1 (pg 47 #1-10)
4.
What energy changes are
considered chemical energy?
The potential energy changes
that result from the destruction
and formation of chemical bonds
are considered chemical energy.
2-1 (pg 47 #1-10)
5.
6.
What is a system? A system is all
of the components that are being
studied at a given time.
Define specific heat capacity.
Specific heat capacity is the
amount of heat required to raise
1 gram of the substance by 1 K.
2-1 (pg 47 #1-10)
7.
What happens in terms of heat
transfer when you hold a
snowball in your hand? Heat
passes from your hand, which is
at a higher temperature, to the
snowball, which is at a lower
temperature.
2-1 (pg 47 #1-10)
8.
a) Which of the metals listed
requires the most energy to raise its
temperature by 1°C? Aluminum.
b) If energy is added at the same
rate to containers all of the same
mass made of copper, chromium,
and lead, which container will show
the greatest rise in temperature after
10 minutes? Lead
2-1 (pg 47 #1-10)
9.
Convert the following Celsius
temperatures to Kelvin
temperatures?
a) 100°C = 373K
b) 785°C = 1058K
c) 0°C = 273K
d) -37°C = 236K
2-1 (pg 47 #1-10)
10.
Convert the following Kelvin
temperatures to Celsius
temperatures?
a) 273K = 0°C
b) 1200K = 927°C
c) 0K = -273°C
d) 100K = -173°C
2-2 (pg 55 #1-11)
1.
What activities are part of the
scientific method? *Refer to the
Scientific Method notes handout.
2-2 (pg 55 #1-11)
2.
How does a hypothesis differ
from a theory? A hypothesis is a
testable explanation for
observations. A theory is also an
explanation of observations, but
it is the result of repeated testing
and revision of hypotheses.
2-2 (pg 55 #1-11)
3.
State the law of conservation of
mass? The total mass of the
products of a reaction is the
same as the total mass of the
reactants.
2-2 (pg 55 #1-11)
4.
What is a scientific law, and how
does it differ from a theory? A
scientific law reliably describes
the observed behavior of the
natural world but does not
explain it. The theory explains
the observed behavior.
2-2 (pg 55 #1-11)
5.
Name two chemical compounds
that were accidentally
discovered, and describe what
they are used for? Penicillin –
treat infections. Saccharine –
sugar substitute.
2-2 (pg 55 #1-11)
6.
Why does a scientist include a
control in the design of an
experiment? A control is used to
isolate the variable a scientist
wants to study.
2-2 (pg 55 #1-11)
7.
Give two reasons why scientists
publish the results of their
experiment. Research results are
published so that researchers are
credited for their work and so
that other scientists can critique
the results and attempt to
replicate them.
2-2 (pg 55 #1-11)
8.
How do models help chemists
acquire knowledge about matter
and energy? Models can be used
to make predictions about the
behavior of matter and energy.
2-2 (pg 55 #1-11)
9.
What variables would a chemist
need to control when setting up an
experiment to determine whether or
not a low temperature is required
for TFE to form a polymer? Ex: the
volume of the reaction vessel, the
mass of the reactants, the pressure
of the reaction system, and the
composition of the reaction mixture.
2-2 (pg 55 #1-11)
9.
What variables would a chemist
need to control when setting up an
experiment to determine whether or
not a low temperature is required
for TFE to form a polymer? Ex: the
volume of the reaction vessel, the
mass of the reactants, the pressure
of the reaction system, and the
composition of the reaction mixture.
2-2 (pg 55 #1-11)
10.
Describe what is needed for a
hypothesis to develop into a
theory? Usually, many
experiments followed by
revision and refinement of the
hypothesis are required.
2-2 (pg 55 #1-11)
11.
Why is there no single scientific
method? Scientists seldom
follow a strict series of steps in
their work.
2-3 (pg 64 #1-12)
1.
How does accuracy differ from
precision? Accuracy indicates
how close a measurement is to
the true value. Precision
indicates how close repeated
measurements are to each other.
2-3 (pg 64 #1-12)
2.
What do the significant figures
in a measurement indicate? The
significant figures in a
measurement are an indication
of the precision of the
measurement.
2-3 (pg 64 #1-12)
3.
Explain the advantage of using
scientific notation? Scientific
notation makes it easier to write
very large values and very small
values.
2-3 (pg 64 #1-12)
4.
What is an exact value? Give an
example. Counts of items and
conversion factors are exact
values. Ex: 1000mm = 1m.
2-3 (pg 64 #1-12)
5.
Describe a problem that may
arise when you use a calculator
to compute an answer.
Calculators cannot make
judgments about significant
figures. Humans must do that.
Therefore, calculator results
must be rounded as needed.
2-3 (pg 64 #1-12)
6.
Why is a burette rather than a
graduated cylinder used when
precise volumes are required in a
lab procedure? Graduated
cylinders can measure only to
the nearest 0.1mL. Most burettes
can measure to the nearest
0.01mL.
7.
2-3 (pg 64 #1-12)
If you measure the mass of
liquid as 11.50g and its volume
as 9.03mL, how many
significant figures should its
density value have? The density
value should have three
significant figures because
9.03mL has only three
significant figures.
2-3 (pg 64 #1-12)
8.
How many significant figures
are there in these expressions?
a) 470km = 3
b) 0.0980m = 3
c) 30.8900g = 6
d) 0.09709kg = 4
2-3 (pg 64 #1-12)
9.
Perform the following calculations, and
express the answers in significant figures.
a) 32.89g + 14.21g = 47.10g
b) 34.09L – 1.230L = 32.86L
c) 3.45 x 105g – 2.6 x 103g= 3.424 x
105g
d) 1.8940cm x 0.0651cm =
0.123cm2
e) 24.897mi/0.8700h = 28.62mi/h
2-3 (pg 64 #1-12)
10.
Express the following calculations in the
proper number of significant figures. Use
scientific notation where appropriate.
a) 129g/29.2mL = 4.42g/mL
b)(1.551mm)(3.260mm)(4.9001mm)
= 24.78mm3
c) 35,000kJ/0.250s = 1.4 x 105kJ/s
d) 0.367L + 2.5L + 1.6004L = 4.48L
11.
2-3 (pg 64 #1-12)
A chemical process produces
653,550kJ of heat in 142.3 min.
What is the rate of heat
production in kJ/min?
4593kJ/min.
2-3 (pg 64 #1-12)
12.
Express the following quantities
in scientific notation.
a) 277,088,000,000,000 atoms =
2.77088 x 1014atoms
b) 0.000000000000839602g =
8.39602 x 10-13g
c) 700,004mm = 7.00004 x
105mm