PRAXIS Science III
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- 1.
Stellar parallax shift can be used to measure the distance between a star and the Earth. So when the parallax shift is larger, which of the following is occurring?
- A.
The closer the star is to Earth.
- B.
The farther the star is from Earth.
- C.
The smaller the parallax angle.
- D.
The easier it is to determine the distance.
Correct Answer
A. The closer the star is to Earth.Explanation
The greater a star shift on a background of stars, the larger the parallax angle; and the closer that the star is to Earth. Through the application of trigonometry we are able to determine that the larger the shift angle, the shorter the distance to Earth.Rate this question:
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- 2.
The latent heat of fusion of water at 0oC is 334 J/g, and its latent heat of vaporization at the same temperature is 2501 J/g. What is the latent heat of sublimation of water at 0oC?
- A.
334 J/g.
- B.
2167 J/g.
- C.
2501 J/g.
- D.
2835 J/g.
Correct Answer
D. 2835 J/g.Explanation
The latent heat of sublimation of a substance at a given temperature is the sum of the latent heat of fusion and the latent heat of vaporization of that substance at that temperature. Thus, the latent heat of sublimation of water at 0oC must be 334 + 2501 J/g = 2835 J/g.Rate this question:
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- 3.
The Biotic Theory is best described by which of the following?
- A.
Changes in climate act as density-dependent agents.
- B.
Populations may be limited by changes in the behavior and physiology of the individuals in the population.
- C.
Populations are limited by the predators that exist in the same geographical area.
- D.
Natural enemies are thought to be the major limiting factor in population growth.
Correct Answer
D. Natural enemies are thought to be the major limiting factor in population growth.Explanation
This is an integral part of the Biotic Theory: Natural enemies will result in a decreased population size. Climatic Theory: Climate is not density-dependent. It affects all organisms equally, regardless of population size. Self-Regulation Theory: Populations may be limited by changes in the behavior and physiology of the individuals in the population. That includes genetics, and has to do with reproduction. A high number of predators will affect the number of prey eventually-but, it does not describe the Biotic Theory.Rate this question:
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- 4.
Which water cycle phase is represented in the graphic?
- A.
Transpiration.
- B.
Precipitation.
- C.
Evaporation.
- D.
Condensation.
Correct Answer
D. Condensation.Explanation
The water cycle phase represented in the graphic is the one in which water vapor is condensed into the clouds. It takes place after evaporation and before precipitation.Rate this question:
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- 5.
Identify the specific element that corresponds to the following electron configuration. [Kr] 5s2 4d10 5p4
- A.
Bromine
- B.
Tellurium
- C.
Antimony
- D.
Strontium
Correct Answer
B. TelluriumExplanation
Electrons 5s2 represent the fifth row on the Periodic Table and the second Column, Electrons 4d10 represent the ten elements in the middle of the Periodic Table (Transition Metals), and the 5p4 is the fifth row and Column 16, Tellurium.Rate this question:
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- 6.
If the “reactant side” of a chemical reaction equation is: 2 NH3(g) + 3 N2O(g) → , then how many atoms of nitrogen must be present on the “product side” of the equation?
- A.
Five (5).
- B.
Six (6).
- C.
Seven (7).
- D.
Eight (8).
Correct Answer
D. Eight (8).Explanation
There must be the same number of atoms of any element on the reactant side and the product side of a chemical reaction equation. There are eight (8) atoms of nitrogen shown on the reactant side, so there must also be eight (8) atoms of nitrogen on the product side.Rate this question:
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- 7.
Any charge can be divided into multiples of a minimum charge which is which of the following?
- A.
1.6x10-19C.
- B.
1C.
- C.
4πε0 C.
- D.
1/(4πε0) C.
Correct Answer
A. 1.6x10-19C.Explanation
The charge of a single electron is 1.6x10-19C. All charges are multiples of that value, since no charge smaller than that quantity has been found.Rate this question:
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- 8.
Human blood pH is closest to which of the following values?
- A.
6.8.
- B.
7.0.
- C.
7.1.
- D.
7.4.
Correct Answer
D. 7.4.Explanation
The lungs and the kidney are constantly adjusting to keep the pH of blood close to 7.4. The lungs can increase or decrease respiration rate to increase or decrease pH, respectively. The kidneys can absorb, secrete, or excrete various compounds to keep blood pH within a narrow range.Rate this question:
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- 9.
What is one of the toughest ethical questions about using technology to extend human life?
- A.
Determining who should live and who should die.
- B.
Determining how this technology should be financed?
- C.
Determining how long we can extend life?
- D.
Determining what is and what isn't a good quality life?
Correct Answer
A. Determining who should live and who should die.Explanation
All of these are tough ethical questions, but the toughest appears to be who should determine who dies and who lives. We cannot know how long lives can be extended. Money should not be an issue, and it is very hard to determine the quality of a life. But it is even harder to determine the fairest way to decide who should live and who should die.Rate this question:
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- 10.
Under which of the following circumstance(s) is a teacher specifically and legally liable?
- A.
When a student sticks himself with a needle.
- B.
When a teacher leaves the classroom unattended, and an injury occurs.
- C.
When a student sneaks a snack into the classroom or laboratory during a biological experiment.
- D.
All of the above.
Correct Answer
B. When a teacher leaves the classroom unattended, and an injury occurs.Explanation
In the course of a day, whether involved in science or not, accidents can happen, and teachers cannot be held responsible. However, a teacher or administrator must be present at all times during an experiment. If the teacher leaves and an accident occurs, the teacher can be held legally accountable and liable.Rate this question:
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- 11.
A total of 800 joules of energy is added to ten (10) grams of a liquid, causing it to increase in temperature from 23oC to 63oC. What is the heat capacity of the liquid?
- A.
2 J/g oC.
- B.
4.18 J/g oC.
- C.
20 J/g oC.
- D.
80 J/g oC.
Correct Answer
A. 2 J/g oC.Explanation
The equation, q = mCpDT can be solved for Cp to give: Cp = q/ mDT = 800/(10)(40) = 2 J/g oC.Rate this question:
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- 12.
When the following redox equation in an acidic solution is balanced, what is the coefficient in front of the chlorine gas? Cr2O72-(aq) + Cl-1(aq) à Cr3+(aq) + Cl2(g)
- A.
6
- B.
3
- C.
2
- D.
1
Correct Answer
B. 3Explanation
The balanced equation is:
14 H+(aq) +Cr2O72-(aq) +6 Cl-1(aq) à 2 Cr3+(aq) +7 H2O(l) + 3Cl2(g)
In acidic solutions redox reactions need H+ ions added to either side of the equation to balance hydrogens. Water is added to balance the oxygen atoms in the original equation.Rate this question:
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- 13.
Charles Darwin is famous for developing the Theory of Evolution, but what other scientist was working on the same idea at the same time?
- A.
Lamarck.
- B.
Pomeroy.
- C.
Wallace.
- D.
Huxley.
Correct Answer
C. Wallace.Explanation
Alfred Wallace independently proposed a theory of evolution due to natural selection, which prompted Darwin to publish his own theory.
Thomas Henry Huxley, an English biologist, became know as "Darwin's Bulldog" for his advocacy of evolution. His 1860 debate with Samuel Wilberforce was a key moment in the wider acceptance for the theory. Jean-Baptist Lemarck was a French naturalist and an early proponent for the idea of evolution. His theory involved a "ladder of complexity" for organisms.Rate this question:
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- 14.
Alfred Wegner is famous for which geological theory?
- A.
Plate Tectonics Theory.
- B.
Uniformitarianism Theory.
- C.
The Continental Drift Theory.
- D.
Mineral Hardness Theory.
Correct Answer
C. The Continental Drift Theory.Explanation
Alfred Wegner was the first person to publicly note how the Continents seemed to fit together. This led to the Theory of Continental Drift, an idea not well received at the time.Rate this question:
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- 15.
Which of the following laws of thermodynamics is an expression of the principle of conservation of energy?
- A.
First law of thermodynamics
- B.
Second law of thermodynamics
- C.
Third law of thermodynamics
- D.
Zeroth law of thermodynamics
Correct Answer
A. First law of thermodynamicsExplanation
The first law of thermodynamics, an expression of the principle of conservation of energy, states that energy can be transformed (changed from one form to another), but it can neither be created nor destroyed. Alternatively, the increase in the internal energy of a system is equal to the amount of energy added by heating the system, minus the amount lost as a result of the work done by the system on its surroundings.Rate this question:
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- 16.
What is the capacitance of a single spherical conductor?
- A.
Zero.
- B.
1/4πr.
- C.
4πr.
- D.
4πε0r.
Correct Answer
D. 4πε0r.Explanation
In a single spherical conductor, the electric field is normal to the surface of the sphere. The potential is given by V=(1/4πε0)Q/r . Since C=Q/V, the capacitance is 4πε0r where ε0 is the permittivity of free space equal to 8.854x10-12 F/m.Rate this question:
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- 17.
When white light is refracted in glass, which of the constituent colors is refracted the most?
- A.
Red.
- B.
Violet.
- C.
Blue.
- D.
Yellow.
Correct Answer
B. Violet.Explanation
The refractive index of glass is inversely proportional to the square of the wavelength of light. The wavelength of red light is the highest, and that of violet is the lowest. Violet-colored light therefore, is refracted the most.Rate this question:
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- 18.
Which of the following is true of the primary growth of a tree?
- A.
It occurs through the activity of the vascular cambium.
- B.
It occurs through the activity of the root cap.
- C.
It occurs only in the first year of the life of the tree.
- D.
It occurs through the activity of the apical meristem.
Correct Answer
D. It occurs through the activity of the apical meristem.Explanation
The apical meristem consists of a small mound of rapidly dividing cells. The cells just below the shoot apical meristem elongate and then mature into differentiated cells of the primary plant stem (or tree trunk in this case). The growth period in cells of the shoot (in both length and diameter) may last longer than the growth period in the root; so growth in the shoot can be detected quite a distance behind the growing tip of the apical meristem.Rate this question:
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- 19.
Which person in history can be considered to be the Father of the Modern Scientific Method?
- A.
Galileo.
- B.
Aristotle.
- C.
Roger Bacon.
- D.
Isaac Newton.
Correct Answer
A. Galileo.Explanation
Galileo is most generally credited with being the father of the scientific method. By developing the tools of observation, hypothesis, mathematical deduction and confirmatory experiment, he founded the scientific methodology that we still use today.Rate this question:
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- 20.
The equation for the dissociation of nitrous acid is: HNO2 = H+ + NO2 - . If a solution of nitrous acid which is 0.0026N has a pH of 3, what is Ka for nitrous acid?
- A.
2 x 10-4.
- B.
2 x 10-5.
- C.
4 x 10-4.
- D.
4 x 10-5.
Correct Answer
C. 4 x 10-4.Explanation
In the sample case,
Ka = [H+][NO2 -] / [HNO2]. Also: [H+] = [NO2 -] = 10-pH = 10-3 = 0.001.
In addition: [HNO2] = normality - [H+] = 0.0026 - 0.0001 = 0.0025.
Substituting values: Ka = (10-3 )( 10-3 )/(0.0025) = (1 x 10-4 )/(0.25) = 4 x 10-4.Rate this question:
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- 21.
Which two criteria are necessary and sufficient for something to be classified as matter?
- A.
It must occupy a fixed volume, and it must have mass.
- B.
It must take up space and it must have mass.
- C.
It must have no net electrical charge, and it must have weight.
- D.
It must take up space, and it must have weight.
Correct Answer
B. It must take up space and it must have mass.Explanation
The first answer choice is not correct because a gas is matter, but does not occupy a fixed volume. The third answer choice is not true because ions are matter, have net electrical charges, and matter that is not in the range of a gravitational force, does not have weight. The fourth choice is not correct because matter that is not in the range of a gravitational force does not have weight. The second answer choice therefore, is the correct answer.Rate this question:
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- 22.
In a safe lab, electricity and which of the following do not mix?
- A.
Open flames.
- B.
Water.
- C.
Chemicals.
- D.
Culture plates.
Correct Answer
B. Water.Explanation
Electricity and water present a shock hazard. In a safe lab, water should be kept away from all electrical equipment.Rate this question:
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- 23.
A motor with an armature of resistance 2Ω is designed to operate at 220V. At full speed, it develops a back emf of 210V. When the motor is switched on, what is the current in the armature if a starter is not used?
- A.
Zero.
- B.
5.0A.
- C.
110A.
- D.
220A.
Correct Answer
C. 110A.Explanation
When the motor is switched on, Eb=0 since the initial speed of the armature is zero. If a starter is not used, the starting current in the armature will be Is= Ea/Ra= 220/2=110A, which is sure to burn out the armature. Hence, a starter must be used with the armature when the motor is initially switched on.Rate this question:
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- 24.
Approximately how high is the higest mountain on Earth?
- A.
About 6,000 meters.
- B.
About 100,000 meters.
- C.
About 10,000 meters.
- D.
About 29,000 meters.
Correct Answer
C. About 10,000 meters.Explanation
Mount Everest is 29,029 feet high, which is about 10,000 meters.Rate this question:
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- 25.
How many ml of a 34,000 mg/L solution of sodium nitrate (NaNO3) will be required to contain 0.1 moles of sodium nitrate? (You may use 85.0 as the molecular weight of sodium nitrate).
- A.
200 ml.
- B.
250 ml.
- C.
300 ml.
- D.
350 ml.
Correct Answer
B. 250 ml.Explanation
The molar concentration of the solution is (34 g/L)/(85 g/mole) = 0.4 moles/L. The number of ml containing 0.1 moles is [(0.1 moles)/(0.4 moles/L)]*(1000 ml/L) = 250 ml.Rate this question:
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- 26.
Theoretically, the absolute lowest temperature is
- A.
-273 K
- B.
-273.15 °F
- C.
0 K
- D.
273 K
Correct Answer
C. 0 KExplanation
Absolute zero which is 0 K or -273.15 °C or -459.68 °F is the temperature when there is no more energy able to be removed. This is the point on the thermodynamic (absolute) temperature scale where all kinetic motion in the particles comprising matter ceases and they are at complete rest in the “classic” (non-quantum mechanical) sense. The Kelvin scale, which a scale of thermodynamic temperature, sets its zero point at absolute zero.Rate this question:
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- 27.
Which of the following refers to the genetic divergence of one or more populations from a single parent species inhabiting the same geographic region, to a degree such that those populations become different species?
- A.
Peripatric speciation.
- B.
Allopatric speciation.
- C.
Parapatric speciation.
- D.
Sympatric speciation.
Correct Answer
D. Sympatric speciation.Explanation
Sympatric speciation is the only one of the four (4) modes of speciation in which one species is originally contained with the range of another.Rate this question:
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- 28.
What does the symbol above mean in organic chemistry?
- A.
Not equal to.
- B.
Stoichiometrically equivalent to.
- C.
Triple bond.
- D.
Three anions.
Correct Answer
C. Triple bond.Explanation
The symbol stands for triple bond, which is usually a bond between two carbon atoms.Rate this question:
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- 29.
While cloud gazing, Bobby tells Susan that he can name three different types of clouds. If he was right, what were three types of clouds that Bobby named?
- A.
Nillostratus, cirrus, and cumulus.
- B.
Cumulus, stratus, and cirrus.
- C.
Nibostratus, columbus, and nimbus.
- D.
Cumbonimbulus, stratus and curious.
Correct Answer
B. Cumulus, stratus, and cirrus.Explanation
The three basic types of clouds are cumulus, stratus and cirrus. There are other more complex cloud types, but these are the three main types.Rate this question:
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- 30.
In a debate, an opponent of organic farming argues that organic food is considered no more nutritious than food that is regularly grown. Which of the following might be an environmental and health-related argument that a pro-organic debator might make in response?
- A.
Pesticides used in conventional food affect other living organisms.
- B.
Organic food tastes better than conventional food.
- C.
Organic food is more visually attractive than conventional food.
- D.
Organic produce is easier to grow than conventional produce.
Correct Answer
A. Pesticides used in conventional food affect other living organisms.Explanation
All of the above might be used in a debate about the merits of organic farming. However, only the argument about pesticides deals mainly with environmental and health concerns, as the question asks.Rate this question:
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- 31.
There used to be nine planets until Pluto was downgraded to a dwarf planet. Which of the following lists includes the eight remaining planets in their order from the sun?
- A.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune, and Uranus.
- B.
Mercury, Venus, Mars, Earth, Jupiter, Saturn, Neptune, and Uranus.
- C.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
- D.
Mercury, Mars, Earth, Venus, Jupiter, Saturn, Neptune, and Uranus.
Correct Answer
C. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.Explanation
The correct order of the eight remaining planets is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.Rate this question:
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- 32.
The Series RLC circuit in the figure is connected to a variable frequency 200V source. L=5H, C=80 μF and R=40Ω. The current amplitude of the circuit at resonance is which of the following?
- A.
50/√2 A.
- B.
5A.
- C.
5√2 A.
- D.
10A.
Correct Answer
C. 5√2 A.Explanation
Current amplitude at resonance is I0= V0/Z= V0/R= √2 Vrms/R= √2 x 200/40= 5√2 A.Rate this question:
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- 33.
In an experiment, data was collected about the level of chemicals present in alluvial wells in alluvial wells in Kansas. Researchers were specifically interested in the amount of nitrate and chloride and whether the two were linked. The data collected was plotted on a scatter plot, which is shown above. Which of the following conclusions would be reasonable based on the data shown?
- A.
Conclusion I: There appears to be no link between the amount of chloride and the amount of nitrate in the well
- B.
Conclusion II: In wells where there was an increased level of chloride, there was generally an increased level of nitrate
- C.
Conclusion III: In wells where there was an increased level of chloride, there was generally a decreased level of nitrate
- D.
Conclusion IV: It is not possible to draw any conclusions from the data
Correct Answer
B. Conclusion II: In wells where there was an increased level of chloride, there was generally an increased level of nitrateExplanation
There appears to be an upwards diagonal trend in the pattern of the data points on the graph. A line has also been drawn in to show the general trend in the data. This shows some level of a positive correlation between chloride and nitrate. The association is not terribly strong, but the association is present.Rate this question:
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- 34.
Two thin lenses of focal lengths f1 and f2 are separated by a distance d. What is the focal length fc of the combined system?
- A.
Fc-1=f1-1-f2-1-df1-1f2-1.
- B.
Fc-1=f1-1+f2-1-df1-1f2-1.
- C.
Fc-1=f1-1+f2-1+df1-1f2-1.
- D.
Fc-1=f1-1*f2-1+df1-1f2-1.
Correct Answer
B. Fc-1=f1-1+f2-1-df1-1f2-1.Explanation
If two thin lenses are separated by a distance d in air, the focal length for the combined system given is : fc-1=f1-1+f2-1-df1-1f2-1.Rate this question:
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- 35.
A missile is fired at your town from maximum range from a place in the enemy country that is 100km away. What is the velocity at which the missile strikes the target, assuming that g=10m/s2?
- A.
102m/s.
- B.
103m/s.
- C.
104m/s.
- D.
105m/s.
Correct Answer
B. 103m/s.Explanation
Given that Rmax=100km=105m. Since the missile is fired from maximum range, the angle of projection is 45°. The initial velocity of the missile is v0=√(g x Rmax)= √(10x105)= 103 m/s.The final velocity is the same as the velocity of projection, which is 103m/s.Rate this question:
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- 36.
What theories is Albert Einstein not famous for?
- A.
The Photoelectric Effect.
- B.
The Theories of Relativity (General and Special).
- C.
The Quantum Uncertainty Principle.
- D.
The Theory of Density Fluctuation in Gases and Liquids.
Correct Answer
C. The Quantum Uncertainty Principle.Explanation
Einstein's name is synonomous with genius, and has many theories connected to it. The Quantum (or Heisenburg) Uncertainty Principle however, is not one.Rate this question:
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- 37.
The meteorological effect of a coastline with high mountains will cause which of the following?
- A.
Higher winds.
- B.
Higher precipitation.
- C.
Lower winds.
- D.
Lower precipitation.
Correct Answer
B. Higher precipitation.Explanation
High mountains in a coastal region will usually cause greater precipitation and heavy, water-ladened clouds must dump some of their water to be able to pass. That is true on the West coasts of both North and South America.Rate this question:
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- 38.
When it is below freezing, rain turns into snow. About how many inches of snow are there in one inch of rain?
- A.
Average ten (10) inches of snow to one (1) inch of rain.
- B.
Average one (1) inch of snow to ten (10) inches of rain.
- C.
They are about equal.
- D.
Snow to liquid equivalents can vary immensely.
Correct Answer
A. Average ten (10) inches of snow to one (1) inch of rain.Explanation
The average equivalent is ten (10) inches of snow being the same as one (1) inch of rain. That varies slightly, depending on how wet the snow is.Rate this question:
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- 39.
How many orders of magnitude difference are there between ten (10) milligrams and 100 kilograms?
- A.
10,000,000.
- B.
Three (3).
- C.
Nine (9).
- D.
Seven (7).
Correct Answer
D. Seven (7).Explanation
First, you must know the prefixes of the metric system: There are 1,000 milligrams in a gram, and 1,000 grams in a kilogram. One way of answering this question is to convert both values into the same unit as follows:
100 kilograms = 100,000,000 milligrams, which is sevenfold greater than ten (10).
Scientists use scientific notation to work with numbers that have many zeros, in order to avoid mistakes, and to make the math more efficient. In our question:
100 kilograms = 1 X 105 grams;
10 milligrams = 1 X 10-2 grams;
Taking the absolute difference 5-(-2) = 7 orders of magnitude.Rate this question:
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- 40.
Tidal waves, or tsunamis can be caused by any of the following forces, EXCEPT which of the following?
- A.
Seismic activity.
- B.
Landslides.
- C.
Tidal bores.
- D.
Volcanoes.
Correct Answer
C. Tidal bores.Explanation
A tidal bore occurs when the leading edge of an incoming tide forms a wave as it travels up a river or narrow bay against the direction of the current. Tidal bores are sometimes called "tidal waves", but they are not true tsunamis.Rate this question:
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- 41.
Which of the following names can be applied to the chemical formula Cu2HPO4? I: Cupric biphosphate. II: Cuprous biphosphate. III: Copper (II) biphosphate. IV: Copper (I) biphosphate.
- A.
I and III.
- B.
II and III.
- C.
I and IV.
- D.
II and IV.
Correct Answer
D. II and IV.Explanation
First you need to determine the charge of the copper ion.
The key to determining this is to know that HPO4 (biphosphate) has a charge of -2
Since HPO4 has a charge of -2, each of two copper ions must have a charge of +1 to make sure the net charge of the molecule is zero
Cu+1 + Cu+1 + (HPO4)-2 = Cu2HPO4
When the copper ion has a charge +1, the name given is "cuprous" or "copper (I)".
So the name of this molecule can be either Cuprous biphosphate or Copper (I) biphosphateRate this question:
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- 42.
What is oxidation number of sulfur in H2SO4?
- A.
-2
- B.
+2
- C.
+6
- D.
-6
Correct Answer
C. +6Explanation
The sum of the charge numbers must equal zero in a compound. Oxygen is -8,
Hydrogen is +2, therefore, Sulfur is +6Rate this question:
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- 43.
Every so often, wind and currents can reiniforce themselves to produce an extremely large wave. This type of wave is called which of the following?
- A.
A tidal wave.
- B.
A rogue wave.
- C.
A tsunami.
- D.
A big wave.
Correct Answer
B. A rogue wave.Explanation
Rogue waves can be generated with the reinforcement of wind and currents up to 120 feet high on the open ocean. It was once thought that rogue waves were very rare, but satellites have shown them to be more common.Rate this question:
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- 44.
What name is given to the molecule that should technically be known as dihydrogen dioxide?
- A.
Hydrogen peroxide.
- B.
Water.
- C.
Ammonia.
- D.
Hydrogen sulfide.
Correct Answer
A. Hydrogen peroxide.Explanation
The name, dihydrogen dioxide indicates that the molecule has two molecules of hydrogen and two of oxygen, thereby given the chemical symbol, H2O2. That is the chemical symbol for hydrogen peroxide. Water is H2O; ammonia is NH3; and hydrogen sulfide is H2S.Rate this question:
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- 45.
An observer moves toward a stationary sound source with a velocity that is one-tenth (1/10th) of the velocity of sound. The apparent increase in frequency is which of the following?
- A.
Zero.
- B.
Five percent (5%).
- C.
Ten percent (10%).
- D.
Zero point one percent (0.1%).
Correct Answer
C. Ten percent (10%).Explanation
F'=F(1+u/v). In the question, the observer moves toward the stationary source at 1/10 the speed of sound u/v=1/10. Therefore F'=(11/10)F and the increase in frequency is (F'-F)/F=0.1=10%.Rate this question:
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- 46.
Human cloning has the potential to provide organs for the sick, but also to create severely deformed beings. There are many ethical points that need to be considered. What do you think that the best course on human cloning should be?
- A.
Allow it in every case.
- B.
Restrict it in every case.
- C.
Restrict it with some degree of freedom.
- D.
Continue doing what we are doing now.
Correct Answer
C. Restrict it with some degree of freedom.Explanation
Totally unrestricted use or totally restricted use seem unwise. Doing what we are already doing is not working. It would seem that restriction with carefully considered exceptions is the best course of action. .Rate this question:
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- 47.
Harold is the only one in his class with red hair. He has the highest grade in the class. James concludes that red hair makes Harold smarter than everyone in his class. Which of the following describes the error that James has made?
- A.
Harold is also the only one with blue eyes, which is more likely to be causing his intelligence.
- B.
Sally also has red hair, but dyes it.
- C.
Harold’s brother is a "D" student, and also has red hair.
- D.
Just because red hair and intelligence occur in the same person, does not mean that red hair causes intelligence.
Correct Answer
D. Just because red hair and intelligence occur in the same person, does not mean that red hair causes intelligence.Explanation
A common mistake in science is to assume a causal link between things, when there is only an association. In the sample case, red hair is associated with good school performance. Much stronger evidence would be to administer a test of intelligence to a large group of people with red hair, and to a large group of people without red hair. If most people with red hair did significantly better than people without red hair, then it may be concluded that people with red hair do better on certain tests than those without red hair.Rate this question:
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- 48.
The failure of a lens to focus all colors to the same point is called which of the following?
- A.
A spherical aberration.
- B.
A chromatic aberration.
- C.
A field curvature.
- D.
A tilt.
Correct Answer
B. A chromatic aberration.Explanation
Chromatic aberration (also called achromatism) refers to the failure of a lens to focus all colors to the same point, and occurs because lenses have a different refractive index for different wavelengths of light (the dispersion of the lens). The refractive index decreases with increasing wavelength.Rate this question:
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- 49.
From the above graph of heat applied versus temperature what approximately is the temperature of vaporization of zinc?
- A.
700 K
- B.
800 K
- C.
1200 K
- D.
1500 K
Correct Answer
C. 1200 KExplanation
The graph shows the heat applied on the y-axis and the temperature on the x-axis. There are 2 discontinuities in the graph. One is close to 700 K and the other at approximately 1200 K. These discontinuities arise as at the point near 700 K zinc melts and changes state from solid to liquid and at around 1200 K zinc changes state from liquid to vapor. When the metal changes to vapor a lot of heat also called the heat of vaporization is required for the state change. This is the reason for the temperature remaining constant even when extra heat is applied. As the metal first melts and then vaporizes, the second discontinuity around 1200 K is the temperature of vaporization.Rate this question:
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- 50.
Which of the following cardiovascular system parts is associated with oxygen leaving the blood; and carbon dioxide entering the blood?
- A.
Arteries.
- B.
Veins.
- C.
Peripheral capillaries.
- D.
Pulmonary (alveolar) capillaries.
Correct Answer
C. Peripheral capillaries.Explanation
Capillaries are blood vessels of very small diameter with very thin walls that are extremely efficient at allowing gases and nutrients to cross into and out of blood. The pulmonary capillaries are associated with carbon dioxide, leaving blood and oxygen entering it, while the peripheral capillaries distribute oxygen to tissue, and remove the cellular respiration waste product, carbon dioxide.Rate this question:
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.jpg "What does the symbol above mean in organic chemistry?")
.jpg "The Series RLC circuit in the figure is connected to a variable frequency 200V source. L=5H, C=80 μF and R=40Ω. The current amplitude of the circuit at resonance is which of the following?")
.jpg "In an experiment, data was collected about the level of chemicals present in alluvial wells in alluvial wells in Kansas. Researchers were specifically interested in the amount of nitrate and chloride and whether the two were linked. The data collected was plotted on a scatter plot, which is shown above. Which of the following conclusions would be reasonable based on the data shown?")
.bmp "From the above graph of heat applied versus temperature what approximately is the temperature of vaporization of zinc?")
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