CART (Chemistry Acceleration Readiness Test) Exam — Questions and Answers

Question 1: Which of the following statements is NOT a postulate of the Kinetic Molecular Theory of ideal gases?

Gas particles are in constant, random, straight-line motion.
The average kinetic energy of gas particles is directly proportional to the absolute temperature (in Kelvin).
Collisions between gas particles are perfectly elastic, meaning no kinetic energy is lost.
The volume of the gas particles themselves is significant compared to the total volume of the container. (Correct answer)

Correct answer: The volume of the gas particles themselves is significant compared to the total volume of the container.

The Kinetic Molecular Theory of ideal gases includes several key postulates. One of these is that the volume of the individual gas particles is considered negligible compared to the vast empty space between them. [4, 12] Therefore, the statement that the particle volume is significant contradicts this fundamental assumption of an ideal gas.

Question 2: What is the law that states that mass is neither created nor destroyed in a chemical reaction?

Law of Conservation of Energy
Law of Conservation of Mass (Correct answer)
Law of Multiple Proportions
Law of Definite Proportions

Correct answer: Law of Conservation of Mass

The Law of Conservation of Mass states that in any closed system, mass is neither created nor destroyed during a chemical reaction. This fundamental law means that the total mass of the reactants must equal the total mass of the products.

Question 3: In a laboratory neutralization reaction, aqueous sulfuric acid (H₂SO₄) is reacted with aqueous potassium hydroxide (KOH). What are the two products formed in this reaction?

Dipotassium oxide (K₂O) and hydrogen sulfide (H₂S)
Potassium sulfite (K₂SO₃) and dihydrogen peroxide (H₂O₂)
Potassium sulfate (K₂SO₄) and water (H₂O) (Correct answer)
Potassium hydride (KH) and sulfurous acid (H₂SO₃)

Correct answer: Potassium sulfate (K₂SO₄) and water (H₂O)

A neutralization reaction between an acid and a base produces a salt and water. In this case, the acid (H₂SO₄) and the base (KOH) react. The cation from the base (K⁺) combines with the anion from the acid (SO₄²⁻) to form the salt potassium sulfate (K₂SO₄). The hydrogen ion from the acid (H⁺) combines with the hydroxide ion from the base (OH⁻) to form water (H₂O).

Question 4: Einstein's equation E = mc² relates mass and energy in nuclear reactions. What does 'c' represent?

The charge of a proton
The concentration of reactants
The specific heat capacity of the nucleus
The speed of light in a vacuum (Correct answer)

Correct answer: The speed of light in a vacuum

In E = mc², c is the speed of light (~3 × 10⁸ m/s); because c² is enormous, even tiny mass losses produce vast amounts of energy.

Question 5: A student needs to prepare 500.0 mL of a 0.500 M sodium chloride (NaCl) solution. How many grams of NaCl are required? (Molar Mass of NaCl ≈ 58.44 g/mol)

29.2 g
58.4 g
117 g
14.6 g (Correct answer)

Correct answer: 14.6 g

To find the mass of NaCl needed, first calculate the number of moles required using the molarity formula: Moles = Molarity × Volume (L). Moles = 0.500 mol/L × 0.5000 L = 0.250 moles. Then, convert moles to grams using the molar mass: Mass = Moles × Molar Mass. Mass = 0.250 mol × 58.44 g/mol = 14.61 g, which rounds to 14.6 g.

Question 6: Which symbol represents the heat of a reaction measured at constant volume?

ΔG
ΔU (or ΔE) (Correct answer)
ΔH
ΔS

Correct answer: ΔU (or ΔE)

Internal energy change (ΔU or ΔE) represents heat flow at constant volume, as measured in a bomb calorimeter.

Question 7: A chemist dissolves 58.44 g of NaCl (1 mole) in 500 g of water. Which of the following correctly describes the concentration of this solution?

2.0 molal (Correct answer)
1.0 molar
2.0 molar
1.0 molal

Correct answer: 2.0 molal

Molality (m) is defined as moles of solute per kilogram of solvent. First, convert the mass of the solvent (water) from grams to kilograms: 500 g = 0.500 kg. Then, calculate the molality: Molality = moles of solute / kg of solvent = 1 mole NaCl / 0.500 kg H₂O = 2.0 m.

Question 8: What is the name of the polyatomic ion with the formula ClO₂⁻?

Perchlorate
Chlorite (Correct answer)
Hypochlorite
Chlorate

Correct answer: Chlorite

This question requires knowledge of the nomenclature for polyatomic oxyanions. The series of chlorine-oxygen anions follows a pattern. ClO₄⁻ is perchlorate, ClO₃⁻ is chlorate, ClO₂⁻ is chlorite, and ClO⁻ is hypochlorite. The '-ate' suffix is used for the ion with more oxygen atoms, and the '-ite' suffix for the ion with fewer oxygen atoms. The 'per-' prefix indicates one more oxygen than the '-ate' ion, and the 'hypo-' prefix indicates one less oxygen than the '-ite' ion.

Question 9: What is the molar mass of iron(III) sulfate, Fe₂(SO₄)₃?

207.75 g/mol
407.87 g/mol
399.88 g/mol (Correct answer)
349.91 g/mol

Correct answer: 399.88 g/mol

To calculate the molar mass of Fe₂(SO₄)₃, you sum the atomic masses of all atoms in the formula. Iron (Fe) has a molar mass of approximately 55.845 g/mol. Sulfur (S) is ~32.065 g/mol, and Oxygen (O) is ~15.999 g/mol. The calculation is: (2 × 55.845) + 3 × (32.065 + 4 × 15.999) = 111.69 + 3 × (96.061) = 111.69 + 288.183 = 399.873 g/mol, which rounds to 399.88 g/mol.

Question 10: Which type of radiation is stopped most easily and cannot penetrate human skin?

Gamma rays
X-rays
Beta particles
Alpha particles (Correct answer)

Correct answer: Alpha particles

Alpha particles are large, heavy, and doubly charged; they lose energy quickly and are stopped by a few centimeters of air or a sheet of paper.

Question 11: A sample of 0.50 moles of an ideal gas is held in a 10.0 L container at a temperature of 298 K. What is the pressure of the gas? (R = 0.0821 L·atm/mol·K)

2.45 atm
0.82 atm
1.22 atm (Correct answer)
12.2 atm

Correct answer: 1.22 atm

This problem requires the use of the Ideal Gas Law, PV = nRT. [9, 23] To find the pressure (P), we can rearrange the equation to P = nRT / V. Plugging in the given values: P = (0.50 mol * 0.0821 L·atm/mol·K * 298 K) / 10.0 L. This calculation results in a pressure of 1.22 atm.

Question 12: If 8 moles of Al react with 3 moles of Fe₂O₃ according to the equation: 2Al + Fe₂O₃ → 2Fe + Al₂O₃, what is the limiting reactant?

Fe
Al
Fe₂O₃ (Correct answer)
Al₂O₃

Correct answer: Fe₂O₃

The limiting reactant is the one that is completely consumed first, thereby stopping the reaction. From the balanced equation, 2 moles of Al react with 1 mole of Fe₂O₃. If we have 8 moles of Al, it would require 8/2 = 4 moles of Fe₂O₃ to react completely. Since only 3 moles of Fe₂O₃ are available, which is less than the 4 moles needed, Fe₂O₃ will run out first and is therefore the limiting reactant.

Question 13: Which of the following single displacement reactions will occur spontaneously according to the metal activity series?

Zn(s) + CuSO₄(aq) → (Correct answer)
Fe(s) + MgCl₂(aq) →
Cu(s) + AlCl₃(aq) →
Ag(s) + HCl(aq) →

Correct answer: Zn(s) + CuSO₄(aq) →

A single displacement reaction occurs when a more reactive element displaces a less reactive element from a compound. According to the activity series, zinc (Zn) is more reactive than copper (Cu), so it will displace copper from copper(II) sulfate. In the other options, the elemental metals (Cu, Ag, Fe) are less reactive than the metal ions they would need to displace (Al³⁺, H⁺, Mg²⁺), so no reaction will occur.

Question 14: Which of the following best describes a hydrogen bond?

A bond formed by the transfer of electrons from hydrogen to another atom
A bond involving shared electrons between hydrogen and another atom
A weak bond between a hydrogen atom in one molecule and a highly electronegative atom in another molecule (Correct answer)
A strong bond between hydrogen and oxygen in a water molecule

Correct answer: A weak bond between a hydrogen atom in one molecule and a highly electronegative atom in another molecule

A hydrogen bond is a weak intermolecular force that forms when a hydrogen atom, already covalently bonded to a highly electronegative atom (like O, N, or F) in one molecule, is attracted to another highly electronegative atom in a different molecule. This attraction is crucial for many biological and chemical properties, such as water's high boiling point.

Question 15: Which of the following molecules is held together by a polar covalent bond?

O₂
H₂O (Correct answer)
CH₄
N₂

Correct answer: H₂O

A polar covalent bond occurs when electrons are shared unequally between two atoms due to a difference in electronegativity. In H₂O, oxygen is significantly more electronegative than hydrogen, pulling the shared electrons closer to itself and creating partial negative and positive charges within the molecule.

Question 16: An unknown element has two naturally occurring isotopes. The first isotope has a mass of 10.0129 amu and an abundance of 19.9%. The second isotope has a mass of 11.0093 amu and an abundance of 80.1%. What is the average atomic mass of this element?

10.01 amu
11.01 amu
10.51 amu
10.81 amu (Correct answer)

Correct answer: 10.81 amu

The average atomic mass is the weighted average of the masses of its isotopes. To calculate it, multiply the mass of each isotope by its fractional abundance and then sum the results: (10.0129 amu * 0.199) + (11.0093 amu * 0.801) = 1.9925671 amu + 8.8184493 amu = 10.8110164 amu. This value, rounded to two decimal places, is 10.81 amu (which corresponds to Boron).

Question 17: What is a nuclear chain reaction?

A reaction that requires a magnetic field to sustain
A series of chemical reactions that produce heat
A sequence of alpha decays in a single isotope
A process where neutrons from fission trigger additional fissions, releasing more neutrons (Correct answer)

Correct answer: A process where neutrons from fission trigger additional fissions, releasing more neutrons

In a chain reaction, each fission event releases neutrons that cause further fissions, creating a self-sustaining cascade of reactions.

Question 18: Isotopes of an element differ in the number of which subatomic particle?

Electrons
Positrons
Neutrons (Correct answer)
Protons

Correct answer: Neutrons

Isotopes are atoms of the same element, meaning they share the same number of protons and thus the same atomic number. They differ in their mass number because they have varying numbers of neutrons in their nucleus, leading to different atomic masses.

Question 19: Which of the following statements best describes the trend of first ionization energy on the periodic table?

It increases down a group and increases from left to right across a period.
It increases down a group and decreases from left to right across a period.
It decreases down a group and increases from left to right across a period. (Correct answer)
It decreases down a group and decreases from left to right across a period.

Correct answer: It decreases down a group and increases from left to right across a period.

First ionization energy is the energy required to remove the outermost electron from a neutral atom. It decreases down a group because the valence electrons are in higher energy levels, are farther from the nucleus, and experience more shielding, making them easier to remove. It increases from left to right across a period because the increasing effective nuclear charge holds the electrons more tightly, requiring more energy to remove one.

Question 20: Which of the following sets of quantum numbers (n, l, m_l, m_s) is invalid for an electron in an atom?

3, 2, -1, +1/2
2, 0, 0, -1/2
4, 3, -4, +1/2 (Correct answer)
1, 0, 0, +1/2

Correct answer: 4, 3, -4, +1/2

The magnetic quantum number, m_l, can only have integer values from -l to +l. In the set (4, 3, -4, +1/2), l=3, so the possible values for m_l are -3, -2, -1, 0, 1, 2, and 3. The value -4 is not allowed, making this set of quantum numbers invalid.

Question 21: A student measures the volume of a liquid using a 100 mL graduated cylinder with markings every 2 mL. The bottom of the meniscus is clearly above the 74 mL mark but below the 76 mL mark, appearing to be halfway between them. Which of the following is the most appropriate recording of this volume?

75.00 mL
75.0 mL
74.5 mL
75 mL (Correct answer)

Correct answer: 75 mL

When reading a graduated instrument, you record all certain digits plus one estimated digit. The markings are every 2 mL (74, 76, 78...). The volume is definitely greater than 74 mL and less than 76 mL. The student can estimate the position between the marks. The halfway point is 75 mL. Since the markings are at the ones place (74, 76), the estimated digit is also in the ones place. Therefore, 75 mL is the correct reading. Reporting 75.0 mL would imply certainty in the ones place and an estimated tenths place, which is not possible with this instrument.

Question 22: What type of bond involves the electrostatic attraction between delocalized electrons and positively charged metal ions?

Ionic bond
Metallic bond (Correct answer)
Hydrogen bond
Covalent bond

Correct answer: Metallic bond

A metallic bond is characterized by the electrostatic attraction between a 'sea' of delocalized valence electrons and the positively charged metal ions. These free-moving electrons are responsible for the unique properties of metals, such as high electrical conductivity and malleability.

Question 23: An atom has an atomic number of 15 and a mass number of 31. How many protons, neutrons, and electrons does a neutral atom of this element have?

31 protons, 15 neutrons, 31 electrons
15 protons, 15 neutrons, 16 electrons
15 protons, 16 neutrons, 15 electrons (Correct answer)
16 protons, 15 neutrons, 16 electrons

Correct answer: 15 protons, 16 neutrons, 15 electrons

The atomic number (Z) is equal to the number of protons. For a neutral atom, the number of electrons is equal to the number of protons. The mass number (A) is the sum of protons and neutrons. Therefore, protons = 15, electrons = 15, and neutrons = Mass Number - Protons = 31 - 15 = 16.

Question 24: Which of the following concentration units is temperature-dependent because it is based on the volume of the solution?

Mole fraction (X)
Molarity (M) (Correct answer)
Mass percent (%)
Molality (m)

Correct answer: Molarity (M)

Molarity is defined as moles of solute per liter of solution. Since the volume of a solution can change with temperature (expand when heated, contract when cooled), molarity is a temperature-dependent unit. Molality, mass percent, and mole fraction are all based on mass or moles, which are not affected by temperature changes.

Question 25: What is the charge of an electron?

Positive
Negative (Correct answer)
Neutral
Variable

Correct answer: Negative

Electrons are fundamental subatomic particles that carry a single negative elementary charge. This negative charge is crucial for their role in forming chemical bonds and interacting with other atoms.

Question 26: A student prepares a solution of hydrochloric acid (HCl), a strong acid, with a concentration of 0.001 M. What is the pH of this solution?

-3
1
3 (Correct answer)
11

Correct answer: 3

The pH of a solution is calculated using the formula pH = -log[H⁺]. Because HCl is a strong acid, it completely dissociates in water, so the hydrogen ion concentration [H⁺] is equal to the molarity of the acid. Therefore, pH = -log(0.001) = -log(10⁻³) = 3.

Question 27: Which of the following compounds requires a Roman numeral in its name?

BaCl₂
FeCl₃ (Correct answer)
Al₂O₃
Na₂S

Correct answer: FeCl₃

Iron (Fe) is a transition metal that can form multiple stable ions (Fe²⁺ and Fe³⁺). Therefore, a Roman numeral is required to specify the charge of the iron cation in the compound. In FeCl₃, chlorine has a charge of -1, and since there are three chlorine atoms, the total negative charge is -3. To balance this, the iron ion must have a charge of +3, so the correct name is Iron(III) Chloride. Barium, aluminum, and sodium are main group metals that form ions with only one predictable charge (Ba²⁺, Al³⁺, and Na⁺ respectively), so no Roman numeral is needed for them.

Question 28: What is the term for the minimum energy required to break all bonds in one mole of a gaseous molecule?

Heat of formation
Activation energy
Bond dissociation energy (Correct answer)
Lattice energy

Correct answer: Bond dissociation energy

Bond dissociation energy is the energy required to homolytically break a specific bond in one mole of gaseous molecules.

Question 29: Under which of the following conditions would a real gas be expected to deviate MOST from ideal gas behavior?

Low temperature and low pressure
High temperature and low pressure
High temperature and high pressure
Low temperature and high pressure (Correct answer)

Correct answer: Low temperature and high pressure

Real gases deviate from ideal behavior because the assumptions of the Kinetic Molecular Theory (negligible particle volume and no intermolecular forces) break down. [23] At low temperatures, gas particles move slower and intermolecular forces become more significant. At high pressures, the particles are forced closer together, making their individual volumes a more significant fraction of the total container volume. Therefore, the combination of low temperature and high pressure causes the most significant deviation from ideal behavior.

Question 30: What type of reaction is represented by the equation: 2H₂ + O₂ → 2H₂O?

Decomposition reaction
Synthesis reaction (Correct answer)
Double displacement reaction
Single displacement reaction

Correct answer: Synthesis reaction

A synthesis reaction, also known as a combination reaction, is characterized by two or more simple reactants combining to form a more complex product. In the given equation, hydrogen and oxygen gases combine to form water, fitting this definition perfectly.

Question 31: Which of the following correctly expresses the number 0.0004075 in scientific notation?

4.075 x 10⁻⁴ (Correct answer)
40.75 x 10⁻⁵
4.075 x 10⁻³
4.075 x 10⁴

Correct answer: 4.075 x 10⁻⁴

Scientific notation requires a single non-zero digit to the left of the decimal point. To convert 0.0004075, the decimal point must be moved four places to the right to get 4.075. Since the original number is less than one, the exponent of 10 is negative. Therefore, the correct scientific notation is 4.075 x 10⁻⁴.

Question 32: If Kc >> 1 for a reaction, the equilibrium mixture contains mostly:

Equal amounts of both
Reactants
Products (Correct answer)
Only catalysts

Correct answer: Products

A large Kc value means the equilibrium lies far to the right, favoring product formation.

Question 33: What is the ground-state electron configuration for a sulfide ion (S²⁻)?

1s²2s²2p⁶3s²3p⁴
1s²2s²2p⁶3s²
1s²2s²2p⁶3s²3p⁶ (Correct answer)
1s²2s²2p⁶3s²3p²

Correct answer: 1s²2s²2p⁶3s²3p⁶

A neutral sulfur atom (S) has an atomic number of 16, so its electron configuration is 1s²2s²2p⁶3s²3p⁴. The sulfide ion (S²⁻) has gained two electrons. These two electrons are added to the outermost shell, which is the 3p subshell. This fills the 3p subshell completely, resulting in the electron configuration 1s²2s²2p⁶3s²3p⁶, which is isoelectronic with the noble gas Argon.

Question 34: According to collision theory, a reaction occurs when molecules collide with:

Any energy at any orientation
Sufficient energy and proper orientation (Correct answer)
Sufficient energy only, regardless of orientation
Any energy but only the correct orientation

Correct answer: Sufficient energy and proper orientation

Collision theory requires both sufficient kinetic energy (≥ Ea) and the correct geometric orientation for a productive collision.

Question 35: Which type of bond is formed when atoms share electrons?

Ionic bond
Hydrogen bond
Metallic bond
Covalent bond (Correct answer)

Correct answer: Covalent bond

A covalent bond is formed when two atoms share one or more pairs of electrons to achieve a stable electron configuration, typically an octet. This sharing occurs predominantly between nonmetal atoms and results in the formation of molecules.

Question 36: Which of the following correctly names the covalent compound N₂O₅?

Dinitrogen pentoxide (Correct answer)
Nitrogen oxide
Dinitrogen oxide
Nitrogen(V) oxide

Correct answer: Dinitrogen pentoxide

For binary covalent compounds (compounds between two nonmetals), Greek prefixes are used to indicate the number of each type of atom. The prefix for two is 'di-' and the prefix for five is 'penta-'. Therefore, N₂O₅ is named dinitrogen pentoxide. The other names are incorrect because they either omit the prefixes or use the stock system (Roman numerals), which is reserved for ionic compounds with variable-charge metals.

Question 37: Consider the elements Fluorine (F), Carbon (C), and Oxygen (O). Which of the following correctly lists these elements in order of increasing atomic radius?

F, C, O
O, F, C
F, O, C (Correct answer)
C, O, F

Correct answer: F, O, C

Atomic radius generally decreases from left to right across a period in the periodic table. This is because as the atomic number increases across a period, the effective nuclear charge increases, pulling the electron shells closer to the nucleus. Fluorine, Oxygen, and Carbon are all in Period 2. Carbon (Group 14) is furthest to the left, followed by Oxygen (Group 16), and then Fluorine (Group 17). Therefore, the order of increasing atomic radius is F < O < C.

Question 38: Nuclear fission is best described as:

A heavy nucleus splitting into two smaller nuclei (Correct answer)
A proton capturing an electron to form a neutron
A nucleus emitting a gamma ray without changing mass
Two light nuclei combining to form a heavier nucleus

Correct answer: A heavy nucleus splitting into two smaller nuclei

Nuclear fission involves the splitting of a heavy nucleus (like uranium-235) into two smaller nuclei, releasing a large amount of energy.

Question 39: What particles make up an alpha particle?

2 protons and 1 neutron
1 proton and 2 neutrons
2 protons and 2 neutrons (Correct answer)
2 electrons and 2 neutrons

Correct answer: 2 protons and 2 neutrons

An alpha particle is identical to a helium-4 nucleus, consisting of 2 protons and 2 neutrons, giving it a charge of +2.

Question 40: In the following redox reaction, which substance is oxidized? 2Fe(s) + 3Cl₂(g) → 2FeCl₃(s)

This is not a redox reaction.
Cl₂
Fe (Correct answer)
FeCl₃

Correct answer: Fe

Oxidation is the loss of electrons, characterized by an increase in oxidation number. Elemental iron (Fe) starts with an oxidation state of 0. In the product, iron(III) chloride (FeCl₃), iron has an oxidation state of +3. Since the oxidation number of iron increases, it is the substance that is oxidized.

Question 41: In a chemical reaction, the substances that are present at the beginning and undergo change are called:

Catalysts
Inhibitors
Products
Reactants (Correct answer)

Correct answer: Reactants

In a chemical reaction, the substances that are present at the beginning and undergo a chemical change are called reactants. These starting materials are consumed during the reaction to form new substances, which are known as products.

Question 42: Consider the following reversible reaction: HCO₃⁻(aq) + H₂O(l) ⇌ H₂CO₃(aq) + OH⁻(aq) Which of the following represents a Brønsted-Lowry conjugate acid-base pair?

HCO₃⁻ and H₂O
HCO₃⁻ and OH⁻
H₂O and OH⁻ (Correct answer)
H₂O and H₂CO₃

Correct answer: H₂O and OH⁻

A conjugate acid-base pair consists of two species that differ by a single proton (H⁺). In this reaction, H₂O acts as an acid by donating a proton to become its conjugate base, OH⁻. Therefore, H₂O and OH⁻ form a conjugate acid-base pair. The other pair is HCO₃⁻ (base) and H₂CO₃ (its conjugate acid).

Question 43: In the following redox reaction, which species acts as the oxidizing agent? 2Na(s) + Cl₂(g) → 2NaCl(s)

Cl₂ (Correct answer)
NaCl
Na
This is not a redox reaction.

Correct answer: Cl₂

The oxidizing agent is the substance that gets reduced (gains electrons) and thereby causes the oxidation of another substance. In this reaction, elemental chlorine (Cl₂) has an oxidation number of 0 and becomes the chloride ion (Cl⁻) in NaCl, with an oxidation number of -1. Since its oxidation number decreased, Cl₂ gained electrons and was reduced, making it the oxidizing agent.

Question 44: Which of the following represents a double displacement reaction?

AB + CD → AD + CB (Correct answer)
A + BC → AC + B
AB → A + B
A + B → AB

Correct answer: AB + CD → AD + CB

A double displacement reaction involves the exchange of ions between two compounds, typically in an aqueous solution. The cations of the two reactants effectively switch places to form two new compounds, following the general form AB + CD → AD + CB.

Question 45: According to the Brønsted-Lowry theory, which of the following best describes an acid?

A substance that can accept a pair of electrons.
A substance that can donate a proton (H⁺). (Correct answer)
A substance that increases the hydroxide ion concentration in water.
A substance that can accept a proton (H⁺).

Correct answer: A substance that can donate a proton (H⁺).

The Brønsted-Lowry theory defines an acid as a species that donates a proton (a hydrogen ion, H⁺) and a base as a species that accepts a proton. An electron pair acceptor is a Lewis acid, and a substance that increases [OH⁻] is an Arrhenius base.

Question 46: A balloon contains 5.0 L of air at 27°C. If the pressure remains constant, to what temperature in Celsius must the balloon be heated to expand its volume to 8.0 L?

43.2°C
480°C
207°C (Correct answer)
753°C

Correct answer: 207°C

This problem requires the use of Charles's Law, which describes the direct relationship between the volume and absolute temperature of a gas at constant pressure (V₁/T₁ = V₂/T₂). [7, 8] First, convert the initial temperature to Kelvin: T₁ = 27°C + 273.15 = 300.15 K. Then, rearrange the formula to solve for the final temperature (T₂): T₂ = (V₂ * T₁) / V₁. Plugging in the values: T₂ = (8.0 L * 300.15 K) / 5.0 L = 480.24 K. Finally, convert the temperature back to Celsius: T₂ = 480.24 K - 273.15 = 207.09°C.

Question 47: According to VSEPR theory, what is the molecular geometry of a molecule with a central atom that has two bonding pairs and two lone pairs of electrons?

Bent (Correct answer)
Trigonal pyramidal
Linear
Tetrahedral

Correct answer: Bent

Valence Shell Electron Pair Repulsion (VSEPR) theory predicts molecular shape based on minimizing repulsion between electron pairs. A central atom with four electron domains (two bonding pairs and two lone pairs) has a tetrahedral electron geometry. However, the molecular geometry is determined only by the positions of the atoms. The two lone pairs repel the bonding pairs more strongly, pushing the bonded atoms closer together and resulting in a bent or angular molecular shape, like in a water molecule (H₂O).

Question 48: At chemical equilibrium, which of the following is true?

The forward and reverse reaction rates are equal (Correct answer)
The reaction has stopped completely
All reactants have been consumed
The concentrations of reactants and products are equal

Correct answer: The forward and reverse reaction rates are equal

At equilibrium, the forward and reverse reactions occur at the same rate, so concentrations remain constant but are not necessarily equal.

Question 49: The density of mercury is 13.6 g/cm³. What is the mass in kilograms (kg) of 2.50 liters (L) of mercury? (Note: 1 L = 1000 cm³)

34,000 kg
34.0 kg (Correct answer)
3.40 kg
0.0340 kg

Correct answer: 34.0 kg

First, convert the volume from liters to cm³: 2.50 L × (1000 cm³/L) = 2500 cm³. Next, use the density formula (mass = density × volume) to find the mass in grams: mass = 13.6 g/cm³ × 2500 cm³ = 34,000 g. Finally, convert the mass from grams to kilograms: 34,000 g × (1 kg / 1000 g) = 34.0 kg. The final answer is reported to three significant figures, consistent with the initial measurements.

Question 50: Nuclear fusion requires extremely high temperatures primarily because:

High temperature provides energy to overcome the electrostatic repulsion between positively charged nuclei (Correct answer)
High temperature increases the mass of the nuclei
High temperature reduces the number of neutrons needed
High temperature causes nuclei to emit alpha particles first

Correct answer: High temperature provides energy to overcome the electrostatic repulsion between positively charged nuclei

Positively charged nuclei repel each other (Coulomb repulsion); extremely high kinetic energy (temperature) is needed for them to get close enough for the strong nuclear force to fuse them.

Question 51: A flexible container holds 25.0 L of a gas at a pressure of 3.50 atm. If the temperature and number of moles of the gas remain constant, what is the new volume if the pressure is increased to 5.00 atm?

17.5 L (Correct answer)
35.7 L
12.5 L
87.5 L

Correct answer: 17.5 L

This question applies Boyle's Law, which states that for a fixed amount of gas at constant temperature, the pressure and volume are inversely proportional (P₁V₁ = P₂V₂). [3, 5] To find the new volume (V₂), we can rearrange the formula to V₂ = (P₁V₁) / P₂. Plugging in the values: V₂ = (3.50 atm * 25.0 L) / 5.00 atm = 17.5 L.

Question 52: To increase the concentration of a saturated aqueous salt solution at a constant temperature, a student should:

Add more water to the solution.
Stir the solution more vigorously.
Add more salt to the solution.
Evaporate some of the water. (Correct answer)

Correct answer: Evaporate some of the water.

In a saturated solution, the maximum amount of solute is already dissolved. Adding more solute will not increase the concentration. Adding more solvent (water) will decrease the concentration (dilution). Stirring only speeds up the rate of dissolving but doesn't change the saturation point. Evaporating the solvent (water) will remove it from the solution, thereby increasing the ratio of solute to solvent and thus increasing the concentration.

Question 53: What is the term for the heat released or absorbed during a chemical reaction at constant pressure?

Entropy change (ΔS)
Enthalpy change (ΔH) (Correct answer)
Gibbs free energy (ΔG)
Internal energy (ΔU)

Correct answer: Enthalpy change (ΔH)

Enthalpy change (ΔH) represents the heat flow in a reaction carried out at constant pressure.

CART (Chemistry Acceleration Readiness Test) Exam

The CART is used at Miami Dade College to assess whether students can bypass CHM 1025 Introductory Chemistry. It covers high school and introductory college chemistry topics in 50 multiple-choice questions within 60 minutes.

Questions

60 min

Time Limit

50%

To Pass

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Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds