# PSSA PREP

Document Sample

```					          PSSA PREP

Sample Questions for You To Answer
Question 1
1. In the late 1800s, surgeons began washing surgical
instruments with antiseptic substances to reduce the
death rate of patients. Which statement explains
why surgeons adopted new cleaning procedures?

A They developed corrosionresistant surgical instruments.
B They developed medications that could stop pain
during surgery.
C They gained an understanding about the periodic table
of the elements.
D They gained an understanding about organisms that
A Instruments with less corrosion would be easier to
clean, but this was not the reason surgeons
cleaned instruments before surgery.
B Pain-reducing medications increased the number
of surgeries; unfortunately, without sterile
techniques, infections often set in.
C An understanding of elements was basically
unrelated to the need for clean surgical
instruments.
D Key: The discovery of the role that microbes play
in infections set this practice in motion.
Problem 2
CdS + I2 + 2HCl CdCl2 + 2HI + S
2. Which change would happen if additional HI
A The amount of CdS would decrease.
B The amount of HCl would decrease.
C The amount of I2 would increase.
D The amount of CdCl2 would increase.
A The amount of CdS would increase as the reaction is
shifted to the left side of the equation.
B The amount of HCl would increase as the reaction is
shifted to the left side of the equation.
C Key: The amount of I2 would increase as the reaction
is shifted to the left side of the equation.
D The amount of CdCl2 would not change.
Problem 3
3. An experiment was conducted to determine the percent
maximum ATP produced during photosynthesis at a light
intensity of 200 lux. What variable was manipulated during
the experiment?                          ATP Production
90

% Maximum ATP production
80
70
60
A ATP production                                           50
40
30                                                      Series1

B light intensity                                          20
10
0

C wavelength of light                                           400   450   500   550    600    650
Wavelength of LIght (nm)
700   750

D percent maximum ATP production
A ATP production is the responding (dependent)
variable.
B Light intensity was held constant.
C Key: The wavelength of light was changed by
the experimenter so it is the manipulated
(independent) variable.
D The maximum ATP production depends on the
wavelength of light, so it is a single data point
for the responding variable
Question 4
Geranium Plant Growth Hypotheses
Hypothesis X:                               Hypothesis Y:
A total of 30 mg of phosphorus              A 30-mg mixture of phosphorus,
week will cause that plant to have          to a geranium plant each week
ten more flower blooms than              will cause that plant to grow
geranium plant without fertilizer        taller, have more blooms, and
after four weeks.                         look better.

4. Which statement accurately evaluates the hypotheses?
A X has one independent variable and a control; Y lacks both.
B Y has one independent variable and a control; X lacks both.
C X has ten dependent variables and no control; Y lacks both.
D Y has three dependent variables and three controls; X lacks both.
A Key: Hypothesis X includes an independent variable (the amount of
phosphorus), a method of measuring the dependent variable (the number
of blooms), and a control (the plant without the phosphorus). Hypothesis Y
is not clearly defined, and “looks better” is an opinion.
B Hypothesis Y has no control. Hypothesis X identifies the control and
independent variable.
C Hypothesis X has only one dependent variable (the number of flowers), and
it has a control.
Hypothesis Y lacks a control, and three dependent variables are identifi ed
(height, number of blooms, and appearance).
D Hypothesis Y has 3 dependent variables (height, number of blooms, and
appearance), but it has
no control. Hypothesis X has one dependent variable and one control.
AB
Question 5
5. A student recorded the temperatures of containers half-filled with either
soil or water each minute for 20 minutes. For the first 10 minutes, a light
was turned on above the containers. For the last 10 minutes, the light
was turned off. Which question could be tested by using this
experimental design?

A How does electricity affect the temperatures of water and soil?
B How does light affect a plant’s growth in water and soil?
C How does the rate of evaporation differ in water and soil?
D How does the rate of heat absorption differ in water and soil?
A No electricity was involved in the setup, therefore the
question cannot be answered with this experiment.
B No plants were involved in the setup, therefore the
question cannot be answered with this experiment.
C Since the amount of water in the containers is not
measured, the evaporation rate cannot be tested by
the setup in this experiment.
D Key: The material that causes the temperature to rise
the most can be assumed to have absorbed heat
faster, therefore this question can be answered since
the temperature can be measured.
Question 6
Inside Dialysis Tubing     Inside Beaker
Starch                     iodine
Students use a pouch of dialysis tubing to model a cell
Glucose                       Water
membrane. A starch and glucose solution is placed inside the
pouch,Solution is colorless is placedSolution is brown that contains
and the pouch                 into a beaker
of 24 hours
iodine After 24 hours An advantageAfterusing the dialysis tubing to
and water.
Starch, glucose, iodine,      Iodine, water, solution is
represent a cell membrane is that it is
solution is blue-black        brown
A permeable to all substances.
B impermeable to all substances.
C permeable to iodine and impermeable to starch.
D impermeable to iodine and permeable to starch.
A If the membrane is permeable to all substances, the solution would become
the same inside the tubing and inside the beaker.
B If the membrane is impermeable to all substances, the fi nal conditions
would be exactly the same as the initial conditions.
C Key: The membrane must be permeable to iodine, because it is found inside
the tubing at the end of the investigation. The membrane must be
impermeable to starch, because the solution in the beaker does not contain
starch at the end of the investigation.
D If the membrane is impermeable to iodine, no iodine would be in the tube in
its fi nal conditions. If the membrane were permeable to starch, the starch
would be present in the beaker’s final conditions.
Question 7
Use the graph below to answer question 10.
Rabbit Population Over Time

10. A large rabbit population is affected by a lethal virus that infects some of
the adult rabbits. What is the best prediction of what will most likely
happen to the rabbit population after the virus is introduced?
A prediction 1 (red)
B prediction 2 (Purple)
C prediction 3 (black)
D prediction 4 (yellow)
A After the virus is introduced, the population will most likely decrease due to
increased mortality.
B After the introduction of the virus, mortality will increase, causing the
population to decrease, rather than maintaining the current population
size.
C Key: Increased mortality will cause a decrease in population, but at some
point, the population will reach equilibrium and remain more or less
constant.
D Since the virus infects only some of the rabbits, it is unlikely that the
population will decrease to zero.
Question 8
Use the table below to answer question 11.
Comparison of Two Bond Types
Bond Type X                          Bond Type Y
makes compounds                       makes molecules
transfers, gives/takes electrons     shares electrons resulting in a
resulting in a noble configuration noble configuration
examples: NaCl, CaCl2                examples: H2O, CO2, NH3, CH4
11. Which of these correctly identifi es the bond types?
A X is ionic. Y is covalent. *
B X is ionic. Y is hydrogen.
C X is covalent. Y is ionic.
D X is hydrogen. Y is covalent.
A Key: Since Type X transfers electrons, it must be ionic. Type Y
makes molecules by sharing electrons, so it must be covalent.
B Since Type X makes compounds, it is ionic. Type Y makes
molecules by sharing electrons, so it cannot be hydrogen.
C Since Type X transfers electrons, it must be ionic rather than
covalent. Type Y makes molecules by sharing electrons, so it
must be covalent rather than ionic.
D Type X results from sharing electrons rather than dipole-dipole
force, so Type X is ionic rather than hydrogen. Type Y makes
molecules by sharing electrons, so it is covalent.
Question 9
2H2(g) + O2(g) 2H2O(g) + 483.6 kJ
9. What is the best description for the energy change
in the chemical reaction?
A Energy is created by the products.
B Energy is absorbed by the reactants.
C Energy is released during the reaction.
D Energy is destroyed during the reaction.
A The creation of energy would be a violation of the fi rst law of
thermodynamics, which states that energy can neither be
created nor destroyed.
B If energy were absorbed by the reactants, the reaction would
be endothermic rather than exothermic.
C Key: 483.6 kJ are released during this exothermic reaction.
D Energy can neither be created nor destroyed, which is the first
law of thermodynamics.
Question 10
10. Which statement explains what would happen to an
astronaut in space after the astronaut throws a rock?
A The astronaut would remain still because of the law of
gravitation.
B The astronaut would move above the rock because of the
law of gravitation.
C The astronaut would move in the same direction that the rock
is moving to match the rock’s momentum.
D The astronaut would move in the opposite direction that the
rock is moving to counter the rock’s momentum.
A The law of gravitation keeps the astronaut in orbit. However,
the conservation of momentum will cause the astronaut to
move in the opposite direction.
B The astronaut will move in space, but this is not due to the law
of gravitation.
Also, the astronaut would move in the opposite direction of the
rock, not upward.
C The astronaut will move in the opposite direction, rather than
in the same direction, as the rock, since momentum is
conserved.
D Key: The opposite directions are an illustration of the
conservation of momentum.
Question 11

11. What is the most likely result of the movement of these two
continental plates?
A the formation of mountains because the plates will fold and
crumple
B the formation of a rift valley because the plates will rebound
after colliding
C the formation of an island because the plates are moving
past one another
D the formation of hot spots because the plates are
generating heat where the plates collide
A Key: Pushing two continental plates together will
cause folding and mountains to form as the crust is
pushed from both sides.
B A rift valley forms when tectonic plates move apart.
C These plates are not moving past each other.
D Hot spots are the results of rising magma. If a
relatively thin plate moves over a hot spot, volcanic
mountains will form rather than folded mountains.
Question 12
12. Which statement explains why an increase in the
atmospheric carbon dioxide (CO2 ) concentration on
Earth concerns climatologists?
A CO2 is hotter than other atmospheric gases.
B CO2 blocks sunlight more than other atmospheric
gases.
C CO2 is a highly reactive substance that destroys
Earth’s surface.
D CO2 traps thermal energy that is radiated towards
space from Earth’s surface.
A Carbon dioxide is the same temperature as the
rest of the air.
B Carbon dioxide does not block sunlight; if it
did, Earth would be cooling.
C Carbon dioxide is a stable gas.
D Key: Carbon dioxide traps thermal (heat)
energy, causing the atmosphere to become
warmer.
Question 13
13. The force of gravity between two objects is inversely
proportional to the square of the distance between objects
(F a 1/d2). How does this relationship help describe the force
of gravity in planetary motion?
A The Sun’s gravitational force on Earth is greater when Earth is
far from the Sun.
B The Sun’s gravitational force on Earth is greater when Earth is
close to the Sun.
C Two identical objects will have a greater force of gravity
between them when they move farther apart.
D Two identical objects will have a smaller force of gravity
between them when they move closer together.
A The force of gravity is least when Earth is farthest from the
Sun.
B Key: Since the force of gravity is inversely related to the
distance between objects, the force of gravity becomes
greater as the distance between Earth and the Sun is reduced.
C Since the force of gravity is inversely related to the distance
between objects, the force becomes less as the distance
becomes greater.
D The closer objects are together, the greater the force of
gravity.
Question 14
14. In the past 300 years, some ocean water
levels have slowly increased. The warming of
the world’s ocean waters is one factor that
can cause this increase.
Part A: Explain how the warming of ocean
water can cause ocean water levels to rise.
Part B: Explain one reason why people should
be concerned about rising water levels in
oceans.
Not quite as good answer for 14
Another Not so Good for 14
Question 15
Not as Good
Poor
Scenario Questions
Take a handout and DON’T LOSE IT!
1. PPAR-d is controlled by a gene already existing in the cells of
the experimental mice. How does the experimental
procedure modify the behavior of the gene?
A It determines whether the gene is dominant or recessive.
B It manipulates the gene so that it is expressed.
C It allows the gene to be beneficial to cells.
D It replicates the gene for use in other cells.
A The dominant or recessive characteristics of a gene were not
studied, and therefore, whether the gene is dominant or
recessive cannot be determined.
B Key: The investigation allowed the gene to be expressed
continuously by modifying its ability to “turn off.”
C The gene may be beneficial to the animal as a whole if it is
obese. Whether the gene is beneficial or not to a specific type
of cell was not discussed.
D The gene is not replicated; it is just“turned on” permanently.
Scenario Question 2
2. How might knowledge gained from Dr. Evans’s
research benefit humans?
A It may alleviate irregular sleep schedules.
B It may partly reverse the health effects of insuffi cient
physical activity.
C It may reduce susceptibility to asthma due to a
smoggy atmosphere.
D It may eliminate problems associated with excessive
exposure to electromagnetic waves.
A The research has nothing to do with sleep, so there is no way
to determine its effect on irregular sleep patterns.
B Key: This option is most likely, since it reduces weight gain and
allows increased metabolism, which in turn allows for more
physical activity.
C The research indicates nothing about breathing, although if
activity were to increase in a smoggy area, then asthma
susceptibility might increase. This would have to be tested.
D The research is based on the regulation of fat burning, not
exposure to electromagnetic waves.
Scenario Question 3
Scenario Free Response
Peroxisomes are extremely small membrane-bound organelles
that store enzymes involved in the metabolism of a number of
types of molecules, including fat. PPAR-d regulates the
number of peroxisomes in fat cells.

Part A: A scientist designs an experiment to test the
effectiveness of the synthetic fat given to mice in the
passage. Identify and describe a reasonable test group and
control group
Part B: Describe two additional experimental design factors
that should be addressed prior to initiating the experiment.