General Science: Content Knowledge 5435 Exam with Complete Solutions
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Course
Praxis 2
Institution
Praxis 2
General Science: Content Knowledge 5435 Exam with
Complete Solutions
Which of the following guidelines should be used when collecting data during an experiment?
Correct answer-Vary only one factor at a time when studying how a system responds.
Which of the following is equivalent to 1 × 10*...
General Science: Content Knowledge 5435 Exam with
Complete Solutions
Which of the following guidelines should be used when collecting data during an experiment?
Correct answer-Vary only one factor at a time when studying how a system responds.
Which of the following is equivalent to 1 × 10*-3 g? Correct answer-1 milligram
Which of the following characteristics is most important in demonstrating that a hypothesis
should be called a theory? Correct answer-It provides an explanation for the results of
many experiments.
Answer the question below by clicking on the correct response.
Question:
Jar 1: Open to air
Jar 2: Opening of jar tightly closed
Jar 3: Opening of jar covered with fine mesh
In an attempt to disprove the belief that living things, such as maggots, can originate
spontaneously from decaying meat, fresh meat was placed in jars as shown above. The
hypothesis that flies are the source of maggots that appear on decaying meat would best be
supported if maggots are later found in which jar? Correct answer-Option (A) is correct.
"Maggot" is the common name for the larvae of certain species of flies, in particular, those that
lay their eggs on fresh meat or carrion. Since flies would not be able to enter jars 2 or 3 to lay
eggs on the meat, maggots would be expected to be found only in jar 1. Francesco Redi
, General Science: Content Knowledge 5435 Exam with
Complete Solutions
conducted this experiment in the seventeenth century, thus disproving the theory of
spontaneous generation.
A thermometer inserted into a solution has a mercury level of just a bit less than halfway
between the markings for 22.4ºC22 point 4 degrees Celsius and 22.5ºC22 point 5 degrees
Celsius. To represent the correct number of significant figures, the temperature of the solution
should be recorded as Correct answer-C. 22.44 For any marked measuring device, one
place beyond the numerical place of the marking is estimated, and this determines the correct
number of significant figures. If the thermometer is marked to 0.1°Czero point one degrees
Celsius, the hundredth place should be estimated and the temperature recorded as 22.44°C22
point four four degrees Celsius.
Experimental evidence supports the fact that most of the mass of an atom is contained in which
of the following? Correct answer-B.The nucleus Option (B) is correct. Ernest Rutherford
published results of his gold foil experiment in 1911. A beam of alpha particles was directed at a
thin sheet of gold foil. Most of the particles passed through the foil, but some were reflected or
deflected, providing experimental evidence that the atom has a relatively small nucleus that
contains most of the mass of the atom.
A student placed 20 radish seeds on a damp paper towel in a petri dish and placed the dish
under a fluorescent light. After 48 hours, all the seeds had germinated. In order for the student
to draw a valid conclusion about the effect of water on seed germination, which of the following
should also have been included in the investigation? Correct answer-In order to draw a
valid conclusion about the effect of water on seed germination, the student should have
included a control experiment, a second dish with a dry paper towel, in the investigation. The
only experimental variable should be the presence or absence of water. The control variables,
, General Science: Content Knowledge 5435 Exam with
Complete Solutions
light and temperature, should be the same for both dishes. C.A second dish with a dry, rather
than damp, paper towel should have been used.
Which of the following will result in a solution of 0.50 M HClzero point five zero molar H C l ?
Correct answer-A.250 mL of 2.0 M HCl added to 750 mL H2O
The concentration of the solution that results from adding 250 mL of 2.0 M HCl to 750 mL7 of
water is 0.50 M. In 250 mL of 2.0 M HCl, there is
0.50 mol of HCl. The total volume after mixing is 1,000 mL or 1.0 L. The concentration of the
solution is 0.50 mol HCl per 1.0 L of solution, which is 0.50 M HCl.
The number of sunspots on the surface of the Sun increases and decreases over an 11-year
period called the solar cycle. The graph above shows how the number of sunspots varied over
50 years. When will the next minimum and the next maximum in the number of sunspots most
likely occur? Correct answer-C.C: data point for the 6-foot drop does not seem to fit the
pattern and the drop should be repeated
Which of the following parts of a compound microscope would be used to regulate the amount
of light transmitted through the specimen on a slide? Correct answer-Diaphragm
Which of the following is a safe laboratory procedure? Correct answer-Preparing a dilute
acid solution by adding a small amount of concentrated acid to water in a flask.
Johannes Kepler's greatest contribution to science was that he Correct answer-
C.described the orbits of the planets as ellipses
, General Science: Content Knowledge 5435 Exam with
Complete Solutions
In 1609, Johannes Kepler published what is now known as Kepler's first law of planetary motion.
Kepler, a mathematician, asserted that observations of the movements of Mars were consistent
with the planet having an elliptical orbit with the Sun as one of the focal points. Kepler's law
refined the Copernican model of the solar system.
One similarity between the Bohr and quantum mechanical models of the atom is that electrons
Correct answer-In both the Bohr and quantum mechanical models, electrons are only in
certain allowed energy states.
When a log burns in a fireplace, producing ash and smoke, which of the following is true?
Correct answer-D.Energy and matter are both conserved. According to the law of
conservation of matter, the total mass of the products is equal to the total mass of the reactants
consumed in the reaction. The law of conservation of energy states that the total energy of an
isolated system remains constant. During the burning of a log, some chemical energy is
converted to thermal energy and light energy and the total energy of the system is constant
Answer the question below by clicking on the correct response.
Question:
ΔG = ΔH − TΔS An equation is shown as follows: Change in Gibbs energy equals change in
enthalpy minus temperature times change in entropy
The change in Gibbs energy for a reaction at constant temperature is given by the equation
above. For an endothermic reaction with ΔH = +20,000 Jchange in enthalpy equals positive
20,000 joules and ΔS = +100 J/Kchange in entropy equals positive 100 joules per kelvin, which of
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