Chemistry Practice Midterm Part 1
This 'quiz' is to help prepare introductory chemistry students for their first midterm.
- 1.
Which branch of chemistry focuses on compounds with carbon?
- A.
Inorganic
- B.
Organic
- C.
Analytical
- D.
Biochemistry
Correct Answer
B. OrganicExplanation
Inorganic deals with substances without carbon. Analytical chemistry focuses on analyzing components of compounds. Biochemistry is the study of chemistry in living organisms. Organic chemistry is focuses on compounds with carbon.Rate this question:
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- 2.
Which of the following is not a step of the scientific method?
- A.
Hypothesis
- B.
Conclusion
- C.
Observations
- D.
Graphing
Correct Answer
D. GrapHingExplanation
The four main steps to the scientific method are observations, hypothesis, experiment, and conclusionRate this question:
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- 3.
What is the goal of the scientific method?
- A.
To prove the hypothesis correct.
- B.
To find a conclusion that you want.
- C.
To explore and test a hypothesis in order to find a conclusion.
- D.
To create a new theory.
Correct Answer
C. To explore and test a hypothesis in order to find a conclusion.Explanation
The intent of the scientific method is never to prove a hypothesis right, but rather to explore and test a hypothesis to find a conclusion.Rate this question:
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- 4.
Which of the following is correct about ozone?
- A.
It shields plants and animals from harmful UV rays.
- B.
It is located in the stratosphere.
- C.
It is made around the equator.
- D.
All of the above is correct.
Correct Answer
D. All of the above is correct.Explanation
All of the options are correct. Ozone is the Earth's protective layer formed around the equator in the stratosphere and moves towards the poles as new ozone is formed.Rate this question:
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- 5.
Covert 4.0 x 103 kilometers to millimeters
- A.
4.0 x 10^3 mm
- B.
4.0 mm
- C.
4.0 x 10^9 mm
- D.
4.0 x 10^-3 mm
Correct Answer
C. 4.0 x 10^9 mmExplanation
(4.0 x 10^3)*(1 x 10^3)*(1 x 10^3)= 4.0 x 10^9Rate this question:
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- 6.
Which of the following is not true about the rules of graphing?
- A.
The independent variable goes on the x axis.
- B.
The dependent variable goes on the x axis.
- C.
Titles should be written as y vs. x.
- D.
The dependent variable is on the y axis.
Correct Answer
B. The dependent variable goes on the x axis.Explanation
When graphing the independent variable is always plotted and labeled from the x axis (horizontal). The dependent variable is located on the y (vertical) axis. Titles should always be written as y vs. x or dependent variable vs. independent variable.Rate this question:
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- 7.
When recording data for a experiment or measurement you should always....
- A.
Record every value you know with certainty.
- B.
Wait to write down numbers until the calculations are finished.
- C.
Count significant digits.
- D.
Record every value you know with certainty plus one estimated digit.
Correct Answer
D. Record every value you know with certainty plus one estimated digit.Explanation
One estimated digit should always be included with all measurements.Rate this question:
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- 8.
Which of the following conversions is correct?
- A.
1000 cm^3 = 1 liter
- B.
1 dm^3 = 100 ml
- C.
1 cm^3 = 100 ml
- D.
They are all incorrect.
Correct Answer
A. 1000 cm^3 = 1 literExplanation
1 cm^3 = 1 ml and 1000 ml =1 liter; therefore 1000 cm^3 = 1 literRate this question:
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- 9.
What is an extensive property?
- A.
A form of qualitative data.
- B.
A property that depends upon the amount of a substance.
- C.
A property that doesn't depend upon the amount of a substance.
- D.
A chemical property that depends upon an external variable.
Correct Answer
B. A property that depends upon the amount of a substance.Explanation
An extensive physical property depends upon the amount of a substance. For example: volume, mass, and length.Rate this question:
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- 10.
Which of the following are a physical changes?
- A.
Leaves changing colors in the fall.
- B.
Dry ice subliming into CO2.
- C.
Copper turning green in moist air.
- D.
Fruit ripening.
Correct Answer
B. Dry ice subliming into CO2.Explanation
Physical changes are changes that do not change the composition of a substance. Dry ice is the solid form of CO2 and subliming is a phase change. All phase changes are physical changes. Examples: boil, freeze, condense, sublime, tear, crumple, ....Rate this question:
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- 11.
Which of the following are chemical changes?
- A.
An explosion
- B.
Iron rusting.
- C.
Frying an egg.
- D.
All the above are chemical changes.
Correct Answer
D. All the above are chemical changes.Explanation
Chemical changes change the composition of a substance. Examples: rot, tarnish, rust, decompose, explode, burn,...Rate this question:
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- 12.
Which of the following are considered a homogeneous mixture?
- A.
Salad
- B.
Vegetable soup
- C.
Water
- D.
Alloy
Correct Answer
D. AlloyExplanation
Homogeneous mixtures are the same throughout but are still two or more physically different substances. Water is a compound not a mixture. Salt water is a well blended mixture of two pure substances and therefore homogeneous. An alloy is a homogeneous mixture of two solids.Rate this question:
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- 13.
How do the properties of a compound relate to the properties of the elements that comprise it?
- A.
The properties of the individual elements do not determine the properties of the compound.
- B.
The element that is most abundant determines the properties of the compound.
- C.
It depends if the ratio is 50/50; if it is, the properties of the compound will be equally shared from the elements.
- D.
The properties of the compound will that of one of the elements. We just don't know which one.
Correct Answer
A. The properties of the individual elements do not determine the properties of the compound.Explanation
The properties of the compound do not relate to the properties of the elements that create it. For example: Water is liquid at room temperature but made from two elements that are gases at room temperature. Table salt is made of two elements, one of which reacts violently with water and the other is a poisonous gas.Rate this question:
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- 14.
What was discovered from the cathode ray tube?
- A.
Protons
- B.
Electrons
- C.
Neutrons
- D.
Atoms
Correct Answer
B. ElectronsExplanation
The cathode ray tube is a vacuum tube with electrodes that when hooked up to electricity form a cathode ray. The cathode ray is composed of electrons and is negatively charged.Rate this question:
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- 15.
What ratio makes an atom neutral?
- A.
1:1 ratio of protons to neutrons
- B.
1:1 ratio of electrons to neutrons
- C.
1:1 ratio of protons to electrons
- D.
None of these. It depends upon the protons only.
Correct Answer
C. 1:1 ratio of protons to electronsExplanation
Protons are positively charged and electrons are negatively charged. Neutrons are neutral. Therefore the ratio between electrons and protons must be equal in order for the charge of an atom to be neutral.Rate this question:
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- 16.
What ratio makes an atom most stable?
- A.
1:1 ratio of protons to neutrons
- B.
1:1 ratio of electrons to neutrons
- C.
1:1 ratio of protons to electrons
- D.
None of these. It depends upon the protons only.
Correct Answer
A. 1:1 ratio of protons to neutronsExplanation
The stability of an atom is dependent on the ratio of the subatomic particles in the nucleus. If the ratio between protons and neutrons is not 1:1, then the atom may undergo a nuclear reaction in order to make the nucleus more stable.Rate this question:
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- 17.
What are isotopes?
- A.
A charged atom that has gained or lost an electron.
- B.
An atom that has a different number of protons.
- C.
An atom that has a different number of neutrons.
- D.
An atom that has a different number of electrons.
Correct Answer
C. An atom that has a different number of neutrons.Explanation
Isotopes are different versions of the same element. The number of protons are the same but the number of neutrons are different. Isotopes will have the same atomic number but different mass numbers.Rate this question:
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- 18.
Which relationship is true?
- A.
Wavelength increases as frequency decreases.
- B.
Wavelength increases as frequency increases.
- C.
Energy increases as frequency decreases.
- D.
Energy decreases as wavelength decreases.
Correct Answer
A. Wavelength increases as frequency decreases.Explanation
E=hv and c=λν. E= energy, v= frequency, c= speed of light (constant), h = Planck's constant. Energy and frequency have a direct relationship. Wavelength and frequency have an indirect relationship. Energy and wavelength have an indirect relationship.Rate this question:
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- 19.
What do the joules measure?
- A.
Atomic radius
- B.
Energy
- C.
Wavelength
- D.
Frequency
Correct Answer
B. EnergyExplanation
Joules are the SI unit for Energy.Rate this question:
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- 20.
What is the SI for frequency?
- A.
Meters
- B.
Joules
- C.
Seconds
- D.
Hertz
Correct Answer
D. HertzExplanation
Frequency is the number of waves per second. Per second (s^-1) is the same as hertz.Rate this question:
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- 21.
Which of the following is true about atomic emission spectra?
- A.
It shows all the colors of the rainbow and therefore all visible wavelengths.
- B.
Each element produces a unique sequence of bright lines.
- C.
It is produced when atoms absorb energy.
- D.
All of the above it correct.
Correct Answer
B. Each element produces a unique sequence of bright lines.Explanation
Atomic emission spectra is unique to every element and can be used to identify elements. It is produced when energy is released from an atom as an electron jumps from an excited state to a ground state.Rate this question:
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- 22.
How many valence electrons are in the following configuration?[Ar] 4s2 3d10 4p4
- A.
2
- B.
10
- C.
4
- D.
6
Correct Answer
D. 6Explanation
Valence electrons are the outermost electrons. In this case, the number of electrons that are in the highest energy level (4) is 6.Rate this question:
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- 23.
What is the octet rule?
- A.
An atom will gain, lose or share electrons to achieve 8 valence electrons.
- B.
The maximum number of valence electrons an atom can have is 8.
- C.
Chemical properties repeat every 8 elements.
- D.
None of the above are correct.
Correct Answer
A. An atom will gain, lose or share electrons to achieve 8 valence electrons.Explanation
The octet rule describes how atoms will gain, lose or share electrons in order to have a complete outer valence shell (8 valence electrons)Rate this question:
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- 24.
Which of the following is/are true?A) Negative ions gain an electron and their radius gets smaller.B) Positive ions gain an electron and their radius gets smaller.C) Negative ions gain an electron and their radius gets larger.D) Positive ions gain an electron and their radius gets larger.E) Negative ions lose an electron and their radius gets smaller.F) Positive ions lose an electron and their radius gets smaller.G) Negative ions lose an electron and their radius gets larger.H) Positive ions lose an electron and their radius gets larger.
- A.
D and E
- B.
B and G
- C.
A and H
- D.
C and F
Correct Answer
D. C and FExplanation
Positive ions have lost one or more electrons. When an ion loses an electron the ion has more protons than electrons and pull the electron clouds closer to the nucleus. Negative ions have gained one or more electrons. When an ion has gained an electron, the electrons repel each other (electrostatic repulsion) and the ion gets largeRate this question:
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- 25.
The control in the experiment....
- A.
Is always held constant.
- B.
Is the same as the dependent variable.
- C.
Is the standard for comparison.
- D.
Is the independent variable.
Correct Answer
C. Is the standard for comparison.Explanation
The control in the experiment is the standard that the results are compared to.Rate this question:
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- 26.
Which of the following are a qualitative observation?
- A.
Temperature
- B.
Time
- C.
Volume
- D.
Color
Correct Answer
D. ColorExplanation
Qualitative observations describe things using the senses. Examples: color, odor, and other visual descriptions.Rate this question:
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- 27.
Which of the following are quantitative measurements?
- A.
Color
- B.
Mass
- C.
Texture
- D.
Odor
Correct Answer
B. MassExplanation
Quantitative observations describe a measurement. Examples: length, mass, temperature, time, ...Rate this question:
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- 28.
In an experiment a student changes the temperature of water in order to measure the solubility of salt in water at different temperatures. The temperature is raised in 5 degree increments and salt is measured and added until it no longer dissolves. What is the independent variable? Dependent variable and control (in order)?
- A.
Temperature, amount of water, amount of salt.
- B.
Amount of water, amount of salt, temperature.
- C.
Temperature, amount of salt, amount of water
- D.
Amount of salt, temperature, amount of water
Correct Answer
C. Temperature, amount of salt, amount of waterExplanation
The independent variable is the variable that is manipulated and controlled in the experiment. The dependent variable changes is response to the independent variable. The control is a point of reference or standard for the experiment.Rate this question:
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- 29.
What is density?
- A.
The amount of matter in an object.
- B.
The amount of matter with the affect of gravity.
- C.
The amount of matter contained in mass
- D.
None of these.
Correct Answer
D. None of these.Explanation
Density is the amount of matter in a specific volume (mass/volume). Mass is the amount of matter in an object. Weight is the measurement of mass and the affect gravity has on it.Rate this question:
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- 30.
How many significant figures are in the following number:0.002400500
- A.
9
- B.
8
- C.
7
- D.
6
Correct Answer
C. 7Explanation
Significant figures include numbers 1-9 and zeros in between these numbers. Zeros at the end (right) of a number with a decimal point are significant and show precision. Placeholder zeros (left) of a number are not significant and can be rewritten in scientific notation without them. Finally, zeros at the end of a number without a decimal point do not show precision and are not significant.Rate this question:
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- 31.
How many significant figures are in the following number: 4500
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2Explanation
Significant figures include numbers 1-9 and zeros in between these numbers. Zeros at the end (right) of a number with a decimal point are significant and show precision. Placeholder zeros (left) of a number are not significant and can be rewritten in scientific notation without them. Finally, zeros at the end of a number without a decimal point do not show precision and are not significantRate this question:
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- 32.
An experiment yields data that a solution has a density of .84 g/ml. The accepted value is .90 g/ml. What is the error of this density measurement?
- A.
.06 g/ml
- B.
- .06 g/ml
- C.
.07 g/ml
- D.
-.07 g/ml
Correct Answer
B. - .06 g/mlExplanation
Error = experimental value - accepted valueRate this question:
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- 33.
An experiment yields data that a solution has a density of .55 g/ml. The accepted value is .65 g/ml. What is the percent error of this density measurement?
- A.
- 10 %
- B.
.10 %
- C.
15%
- D.
-.15 %
Correct Answer
C. 15%Explanation
Percent error = [(experimental value - accepted value)/accepted value] x 100%Rate this question:
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- 34.
What is the correct sum of the following numbers with significant figures:12.345 + 8.67 + 31.021
- A.
52.036
- B.
52.03
- C.
52.04
- D.
52.0
- E.
52.
Correct Answer
C. 52.04Explanation
When adding or subtracting numbers, significant digits in the answer should reflect the least precise number that your adding/subtracting. In this case, 8.67 is the least precise number because it only has two numbers after the decimal point and not three. So the answer can only have two numbers after the decimal point.Rate this question:
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- 35.
What is the correct product of the following numbers with significant figures:120 x 15.64
- A.
1876.8
- B.
1877
- C.
1880
- D.
1900
Correct Answer
D. 1900Explanation
When multiplying or dividing numbers the answer will have the same number of significant digits in it as the number being multiplied or divided with the least number of significant digits in it. In this case, 15.64 has 4 sig figs. 120 has only 2 sig figs. So the answer should have 2 sig figs in it.Rate this question:
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- 36.
What is the product of 2.4 x 103 cm and 4.32 x 102 m?
- A.
1.04 x 10^8 cm2
- B.
1.04 x 10^5 m2
- C.
1.04 x 10^4 m2
- D.
1.0 x 10^8 cm2
Correct Answer
D. 1.0 x 10^8 cm2Explanation
When multiplying these numbers, the units first must be the same. Once converted, the exponents in the scientific notation must be added. 4.32 x 10^2 m = 4.32 x 10^4 cm. 4.32 x 10^4 cm x 2.4 x 10^3 cm = 1.0368 x 10^8 cm2. Final answer with sig figs: 1.0 x 10^8 cm2Rate this question:
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- 37.
Which of the following is an intensive property?
- A.
Volume
- B.
Density
- C.
Mass
- D.
Length
Correct Answer
B. DensityExplanation
An intensive property is a physical property that is not dependent on the amount of that substance. Examples: color, boiling pt., freezing pt., density....Rate this question:
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- 38.
What is sublimation?
- A.
The process of a liquid becoming a gas.
- B.
The process of a solid becoming a gas.
- C.
The process of a solid becoming a liquid.
- D.
The process of a liquid becoming a solid.
Correct Answer
B. The process of a solid becoming a gas.Explanation
Sublimation is the phase change of a solid becoming a gas. At the right temperature a solid mixture may be separated using sublimation.Rate this question:
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- 39.
Which of the following are a heterogeneous mixture?
- A.
Carbon dioxide
- B.
Salt water
- C.
Tin
- D.
Salad
Correct Answer
D. SaladExplanation
Heterogeneous mixtures are physical mixtures in which the substances do not blend well and retain their individual properties. Examples: salad, vegetable soup , sand and water, ...Rate this question:
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- 40.
Which of the following separation techniques is used to separate a heterogeneous mixture?
- A.
Crystallization
- B.
Distillation
- C.
Chromatography
- D.
Filtration
Correct Answer
D. FiltrationExplanation
Crystallization separates a homogeneous mixture by allowing a crystal to form and remove a solid from a liquid. Distillation separates a homogeneous mixtures based on the differences of boiling points. Chromatography separates homogenous mixtures based on a substance's attraction and movement across a material. Filtration separates heterogeneous mixtures with the use of a porous barrier.Rate this question:
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Mar 21, 2023Quiz Edited by
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Jan 08, 2011Quiz Created by
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