Chemistry Tutor Competency Quiz
Questions and Answers
- 1.
Which of the following statements describes the difference between endothermic and exothermic chemical reactions?
- A.
Energy is conserved in endothermic reactions but is not conserved in exothermic reactions.
- B.
Endothermic reactions involve changes in the nucleus of an atom, but exothermic reactions do not involve changes in the nucleus.
- C.
Energy is absorbed in endothermic reactions but is released in exothermic reactions.
- D.
Endothermic reactions occur when electrons are shared between atoms, but exothermic reactions occur when electrons are transferred between atoms.
Correct Answer
C. Energy is absorbed in endothermic reactions but is released in exothermic reactions.Explanation
Endothermic reactions involve the absorption of energy, while exothermic reactions involve the release of energy. This means that in endothermic reactions, energy is taken in from the surroundings, while in exothermic reactions, energy is given off to the surroundings.Rate this question:
-
- 2.
Which of the following is an intensive property?
- A.
Mass
- B.
Volume
- C.
Density
- D.
Length
Correct Answer
C. DensityExplanation
An intensive property is a property that does not depend on the amount or size of the substance. Density is an intensive property because it is a ratio of mass to volume, meaning it remains constant regardless of the amount of substance present. In contrast, mass, volume, and length are extensive properties, as they depend on the amount or size of the substance.Rate this question:
-
- 3.
Which physical method of separating mixtures would you use to separate colors in a dye?
- A.
Chromatography
- B.
Separating funnel
- C.
Centrifugation
- D.
Simple distillation
Correct Answer
A. ChromatographyExplanation
Chromatography is a physical method of separating mixtures based on the differences in the components' ability to be carried by a mobile phase. In the case of separating colors in a dye, chromatography can be used because different colors have different affinities for the mobile phase. As the mobile phase moves through a stationary phase, the colors will separate based on their interactions with the stationary phase, allowing for the individual colors to be collected and analyzed.Rate this question:
-
- 4.
The process of splitting atoms is called ____________.
- A.
Nuclear fusion
- B.
Nuclear fission
- C.
Radioactive decay
- D.
None of the above
Correct Answer
B. Nuclear fissionExplanation
Nuclear fission is the correct answer because it refers to the process of splitting atoms. In nuclear fission, the nucleus of an atom is split into two or more smaller nuclei, releasing a large amount of energy. This process is commonly used in nuclear power plants and atomic bombs. Nuclear fusion, on the other hand, is the process of combining two or more atomic nuclei to form a larger nucleus, which also releases a significant amount of energy. Radioactive decay, while related to nuclear processes, does not involve the splitting of atoms.Rate this question:
-
- 5.
Molecular Orbital Theory describes the respective bond orders in H₂ , H₂ + , and H₂ – as _____________.
- A.
1, 0, and 0
- B.
1, 0, and ½
- C.
1, ½, and ½
- D.
1, ½, and 0
Correct Answer
C. 1, ½, and ½Explanation
The Molecular Orbital Theory describes the respective bond orders in H₂, H₂+, and H₂- as 1, ½, and ½. In H₂, both hydrogen atoms contribute one electron to form a bonding molecular orbital, resulting in a bond order of 1. In H₂+, one hydrogen atom donates both its electrons to form a bonding molecular orbital, while the other hydrogen atom remains unaltered, resulting in a bond order of ½. In H₂-, one hydrogen atom retains both its electrons to form an antibonding molecular orbital, while the other hydrogen atom donates both its electrons to form a bonding molecular orbital, resulting in a bond order of ½.Rate this question:
-
- 6.
A triple bond consists of _________________.
- A.
Three sigma bonds
- B.
One sigma and two pi bonds
- C.
Three pi bonds
- D.
Two sigma and one pi bond
Correct Answer
B. One sigma and two pi bondsExplanation
A triple bond consists of one sigma bond and two pi bonds. The sigma bond is formed by the overlap of two atomic orbitals head-on, while the pi bonds are formed by the sideways overlap of p orbitals. The presence of two pi bonds in a triple bond allows for greater electron density and a stronger bond compared to a double bond, which consists of one sigma and one pi bond.Rate this question:
-
- 7.
The proper name for N₂O₅ is _______________.
- A.
Nitrogen pentoxide
- B.
Dinitrogen pentoxide
- C.
Nitrous oxide
- D.
Pentaoxidgen dinitride
Correct Answer
B. Dinitrogen pentoxideExplanation
The proper name for N₂O₅ is dinitrogen pentoxide because the compound consists of two nitrogen atoms (di-) and five oxygen atoms (-pentoxide).Rate this question:
-
- 8.
Which list of formulas represents compounds, only?
- A.
CO₂, H₂O, NH₃
- B.
H₂, N₂, O₂
- C.
H₂, Ne, NaCl
- D.
MgO, NaCl, O₂
Correct Answer
A. CO₂, H₂O, NH₃Explanation
The given list of formulas, CO₂, H₂O, NH₃, represents compounds only because these formulas consist of multiple elements chemically bonded together. CO₂ is the formula for carbon dioxide, which is a compound composed of carbon and oxygen atoms. H₂O is the formula for water, which is a compound composed of hydrogen and oxygen atoms. NH₃ is the formula for ammonia, which is a compound composed of nitrogen and hydrogen atoms. In contrast, the other options contain elements or compounds that are not chemically bonded together.Rate this question:
-
- 9.
Mass of an empty container = 3.0 grams Mass of the container plus the solid sample = 25.0 grams Volume of the solid sample = 11.0 cubic centimeters The data above were gathered in order to determine the density of an unknown solid. The density of the sample should be reported as
- A.
0.5 g/cm3
- B.
0.50 g/cm3
- C.
2.0 g/cm3
- D.
2.00 g/cm3
Correct Answer
D. 2.00 g/cm3Explanation
The density of a substance is calculated by dividing its mass by its volume. In this case, the mass of the solid sample is determined by subtracting the mass of the empty container from the mass of the container plus the solid sample, which is 25.0 grams - 3.0 grams = 22.0 grams. The volume of the solid sample is given as 11.0 cubic centimeters. Dividing the mass (22.0 grams) by the volume (11.0 cubic centimeters) gives a density of 2.00 g/cm3.Rate this question:
-
- 10.
If 87.5 percent of a sample of pure 131I decays in 24 days, what is the half-life of 131I?
- A.
6 days
- B.
8 days
- C.
12 days
- D.
14 days
Correct Answer
B. 8 daysExplanation
The half-life of a radioactive substance is the time it takes for half of the sample to decay. In this question, we are given that 87.5 percent of the sample decays in 24 days. Since half of the sample decays in the half-life, we can calculate the half-life by dividing 24 days by 87.5 percent, which is equivalent to multiplying by 100 and then dividing by 87.5. This calculation gives us a half-life of 8 days.Rate this question:
-
- 11.
Body temperature is 98.6°F. What is the temperature in °C?
- A.
32 degrees
- B.
37 degrees
- C.
39 degrees
- D.
40 degrees
Correct Answer
B. 37 degreesExplanation
To convert Fahrenheit to Celsius, you can use the formula: °C = (°F - 32) / 1.8. Plugging in the given temperature of 98.6°F into the formula, we get (98.6 - 32) / 1.8 = 66.6 / 1.8 = 37°C. Therefore, the correct answer is 37 degrees.Rate this question:
-
- 12.
Which equation represents an oxidation reduction reaction?
- A.
CH₄ + 2O₂ ==> CO₂ + 2H₂O
- B.
H₂SO₄ + Ca(OH)₂ ==> CaSO₄ + 2H₂O
- C.
MgCrO₄ + BaCl₂ ==> MgCl₂ + BaCrO₄
- D.
Zn(NO₃)₂ + Na2CO₃ ==> 2NaNO₃ + ZnCO₃
Correct Answer
A. CH₄ + 2O₂ ==> CO₂ + 2H₂OExplanation
The equation CH₄ + 2O₂ ==> CO₂ + 2H₂O represents an oxidation-reduction reaction because there is a transfer of electrons between the reactants and products. In this reaction, methane (CH₄) is oxidized to carbon dioxide (CO₂) by gaining oxygen (O₂), while oxygen (O₂) is reduced to water (H₂O) by gaining hydrogen (H₂). This transfer of electrons indicates a redox reaction, which is characteristic of oxidation-reduction reactions.Rate this question:
-
- 13.
A single protron has what electrical charge?
- A.
No Charge
- B.
Positive Charge
- C.
Negative Charge
- D.
Either a Positive or Negative Charge
Correct Answer
B. Positive ChargeExplanation
A single proton has a positive charge because it contains one unit of positive electrical charge. Protons are subatomic particles found in the nucleus of an atom and are positively charged, while electrons, which orbit the nucleus, have a negative charge. The positive charge of a proton is equal in magnitude to the negative charge of an electron, resulting in a neutral atom.Rate this question:
-
- 14.
What is the fourth most abundant element in the universe in terms of mass?
- A.
Sodium
- B.
Boron
- C.
Helium
- D.
Carbon
Correct Answer
D. CarbonExplanation
Carbon is the correct answer because it is the fourth most abundant element in the universe in terms of mass. It is found in various forms, such as graphite and diamond, and is a key component of organic compounds. Carbon is essential for life on Earth and plays a crucial role in many biological processes.Rate this question:
-
- 15.
How many moles of solid Ba(NO3)2 should be added to 300. milliliters of 0.20-molar Fe(NO3)3 to increase the concentration of the NO3¯ ion to 1.0-molar? (Assume that the volume of the solution remains constant.)
- A.
0.060 mole
- B.
0.12 mole
- C.
0.24 mole
- D.
0.30 mole
Correct Answer
A. 0.060 moleExplanation
To increase the concentration of the NO3- ion to 1.0-molar, the moles of NO3- ions in the solution need to be equal to the moles of NO3- ions in the solid Ba(NO3)2. Since the molar ratio between Ba(NO3)2 and NO3- ions is 1:2, we need half the moles of Ba(NO3)2 to achieve the desired concentration.
Given that the volume of the solution remains constant, we can use the formula:
Moles = Molarity × Volume
Moles of NO3- ions in the solution = 0.20 mol/L × 0.300 L = 0.060 mol
Therefore, 0.060 mole of solid Ba(NO3)2 should be added to achieve the desired concentration of the NO3- ion.Rate this question:
-
Quiz Review Timeline +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
-
Current Version
-
Mar 14, 2023Quiz Edited by
ProProfs Editorial Team -
Feb 24, 2014Quiz Created by
Mucas
Am I Pretty, Cute, Or Beautiful? Unlock Your Beauty Potential
Am I Pretty, Cute, Or Beautiful? Unlock Your Beauty Potential
Teacher Personality Test: What Is Your Teacher Personality?
Teacher Personality Test: What Is Your Teacher Personality?
Back to top