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

Question 1: Which of the following will increase the rate of most chemical reactions?

Decreasing reactant concentration
Increasing surface area of solid reactants (Correct answer)
Removing a catalyst
Decreasing temperature

Correct answer: Increasing surface area of solid reactants

Increasing surface area exposes more reactant particles to collisions, increasing the frequency of effective collisions and the reaction rate.

Question 2: Which of the following represents a double displacement reaction?

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

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

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

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 4: 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?

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

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 5: What is the correct chemical formula for the ionic compound formed between magnesium and the phosphate polyatomic ion?

Mg₃(PO₄)₂ (Correct answer)
MgPO₄
Mg₂(PO₄)₃
Mg(PO₄)₂

Correct answer: Mg₃(PO₄)₂

Magnesium (Mg), an alkaline earth metal in Group 2, forms a cation with a +2 charge (Mg²⁺). The phosphate polyatomic ion has the formula PO₄³⁻ and a charge of -3. To form a neutral compound, the total positive charge must equal the total negative charge. The least common multiple of 2 and 3 is 6. Therefore, three Mg²⁺ ions (3 x +2 = +6) are needed to balance two PO₄³⁻ ions (2 x -3 = -6). The correct formula is Mg₃(PO₄)₂.

Question 6: 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?

207°C (Correct answer)
43.2°C
480°C
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 7: Which of the following is a balanced equation for the combustion of methane (CH₄)?

CH₄ + 2O₂ → CO₂ + 2H₂O (Correct answer)
CH₄ + O₂ → CO₂ + H₂O
CH₄ + 3O₂ → 2CO₂ + 2H₂O
CH₄ + O₂ → CO + H₂O

Correct answer: CH₄ + 2O₂ → CO₂ + 2H₂O

To balance the combustion of methane (CH₄), the number of atoms for each element must be equal on both sides of the equation. One carbon atom on the left requires one CO₂ on the right. Four hydrogen atoms on the left require two H₂O on the right (2*2=4). This then results in four oxygen atoms on the right (2 from CO₂ + 2 from 2H₂O), which means two O₂ molecules are needed on the left (2*2=4).

Question 8: 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?

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

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

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

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 10: What is the atomic number of an element?

The number of electrons in an atom's nucleus
The number of protons in an atom's nucleus (Correct answer)
The total number of protons and neutrons in an atom's nucleus
The number of neutrons in an atom's nucleus

Correct answer: The number of protons in an atom's nucleus

The atomic number (Z) is fundamentally defined by the number of protons found in an atom's nucleus. This unique count of protons determines the identity of an element and its position on the periodic table, distinguishing it from all other elements.

Question 11: 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
Tetrahedral
Linear

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 12: Aqueous solutions of lead(II) nitrate, Pb(NO₃)₂, and potassium iodide, KI, are mixed, resulting in the formation of a solid precipitate. What is the correct net ionic equation for this reaction?

Pb²⁺(aq) + 2I⁻(aq) → PbI₂(s) (Correct answer)
Pb²⁺(aq) + 2NO₃⁻(aq) + 2K⁺(aq) + 2I⁻(aq) → PbI₂(s) + 2KNO₃(s)
K⁺(aq) + NO₃⁻(aq) → KNO₃(s)
Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq)

Correct answer: Pb²⁺(aq) + 2I⁻(aq) → PbI₂(s)

The balanced molecular equation is Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq). The spectator ions, which do not participate in the formation of the precipitate, are K⁺(aq) and NO₃⁻(aq). Removing these from the complete ionic equation leaves the net ionic equation, which shows only the species that react to form the solid lead(II) iodide.

Question 13: 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?

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

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 14: 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
12.2 atm
1.22 atm (Correct answer)

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

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

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

FeCl₃ (Correct answer)
BaCl₂
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 17: Which factor does NOT affect the value of the equilibrium constant Kc?

Nature of the reaction
Temperature
Pressure (for some reactions)
Concentration of reactants (Correct answer)

Correct answer: Concentration of reactants

Kc depends only on temperature; changing concentrations shifts the position of equilibrium but does not change the value of Kc.

Question 18: The nuclear binding energy of a nucleus represents:

The heat produced during a fission chain reaction
The energy released when electrons bond to form a molecule
The energy needed to remove one electron from the atom
The energy required to completely separate a nucleus into its individual protons and neutrons (Correct answer)

Correct answer: The energy required to completely separate a nucleus into its individual protons and neutrons

Nuclear binding energy is the minimum energy needed to disassemble a nucleus into its constituent free protons and neutrons; it reflects nuclear stability.

Question 19: A student performs a calculation to determine the volume of a rectangular block. The measured dimensions are 12.20 cm, 3.45 cm, and 1.9 cm. What is the volume of the block reported to the correct number of significant figures?

80 cm³ (Correct answer)
80.0 cm³
79.959 cm³
79.96 cm³

Correct answer: 80 cm³

The volume is calculated by multiplying the length, width, and height: 12.20 cm × 3.45 cm × 1.9 cm = 79.959 cm³. When multiplying or dividing measured values, the result must be rounded to the same number of significant figures as the measurement with the fewest significant figures. The measurements have four (12.20), three (3.45), and two (1.9) significant figures, respectively. Therefore, the answer must be rounded to two significant figures, which is 80 cm³.

Question 20: What particles make up an alpha particle?

1 proton and 2 neutrons
2 protons and 1 neutron
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 21: What is the charge of an electron?

Variable
Positive
Neutral
Negative (Correct answer)

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 22: 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 OH⁻
H₂O and OH⁻ (Correct answer)
HCO₃⁻ and H₂O
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 23: 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 (Correct answer)
11
1
-3

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 24: If a radioactive sample has a half-life of 5 years, what fraction of the original sample remains after 15 years?

1/16
1/4
1/2
1/8 (Correct answer)

Correct answer: 1/8

15 years = 3 half-lives; after each half-life the sample halves: (1/2)^3 = 1/8 of the original remains.

Question 25: In beta-minus decay, a neutron is converted inside the nucleus into:

A proton and an emitted electron (beta particle) (Correct answer)
Two protons and a positron
A proton and an emitted positron
An alpha particle and a gamma ray

Correct answer: A proton and an emitted electron (beta particle)

Beta-minus decay: n → p + e⁻ + antineutrino; the proton stays in the nucleus and the electron (beta particle) is emitted.

Question 26: How many grams of CO₂ are produced when 44 grams of propane (C₃H₈) undergo complete combustion according to the equation: C₃H₈ + 5O₂ → 3CO₂ + 4H₂O? (Molar masses: C₃H₈ = 44 g/mol, CO₂ = 44 g/mol)

132 grams (Correct answer)
88 grams
176 grams
44 grams

Correct answer: 132 grams

To solve this, we first convert the given mass of propane (C₃H₈) to moles using its molar mass (44 g/mol), which gives 1 mole of C₃H₈. According to the balanced chemical equation, 1 mole of C₃H₈ produces 3 moles of CO₂. Therefore, 1 mole of propane will produce 3 moles of CO₂. Finally, we convert these 3 moles of CO₂ back to grams using its molar mass (44 g/mol), resulting in 3 * 44 = 132 grams of CO₂.

Question 27: 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
117 g
14.6 g (Correct answer)
58.4 g

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 28: Which of the following correctly names the covalent compound N₂O₅?

Nitrogen(V) oxide
Dinitrogen pentoxide (Correct answer)
Dinitrogen oxide
Nitrogen 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 29: A chemist completely reacts 13.08 g of zinc metal (Zn) with an excess of hydrochloric acid (HCl) according to the balanced equation: Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g). What volume of hydrogen gas (H₂) is produced at Standard Temperature and Pressure (STP)? (Molar mass of Zn = 65.38 g/mol)

1.12 L
2.24 L
8.96 L
4.48 L (Correct answer)

Correct answer: 4.48 L

First, convert the mass of zinc to moles: 13.08 g Zn / 65.38 g/mol = 0.200 mol Zn. The mole ratio between Zn and H₂ is 1:1, so 0.200 mol of H₂ is produced. At STP (0°C and 1 atm), one mole of any ideal gas occupies 22.4 L. Therefore, the volume is 0.200 mol H₂ × 22.4 L/mol = 4.48 L.

Question 30: Under which of the following conditions would a real gas be expected to deviate MOST from ideal gas behavior?

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

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

N₂
H₂O (Correct answer)
O₂
CH₄

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 32: 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)

34.0 kg (Correct answer)
34,000 kg
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 33: Which of the following statements is NOT a postulate of the Kinetic Molecular Theory of ideal gases?

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)
The average kinetic energy of gas particles is directly proportional to the absolute temperature (in Kelvin).
Gas particles are in constant, random, straight-line motion.

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

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

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

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

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 36: A solution is prepared by dissolving 20.0 g of glucose (C₆H₁₂O₆) in 80.0 g of water. What is the mass percent of glucose in this solution?

80.0%
25.0%
100.0%
20.0% (Correct answer)

Correct answer: 20.0%

Mass percent is calculated as (mass of solute / mass of solution) × 100%. The mass of the solute is 20.0 g of glucose. The mass of the solution is the mass of the solute plus the mass of the solvent (20.0 g + 80.0 g = 100.0 g). Therefore, the mass percent is (20.0 g / 100.0 g) × 100% = 20.0%.

Question 37: Standard enthalpy of formation (ΔH°f) for an element in its standard state is:

0 kJ/mol (Correct answer)
Varies by element
–1 kJ/mol
1 kJ/mol

Correct answer: 0 kJ/mol

By definition, the standard enthalpy of formation of any element in its most stable standard state is exactly zero.

Question 38: Which of the following statements best describes the trend of first ionization energy on the periodic table?

It decreases 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 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.

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 39: Nuclear fission is best described as:

A nucleus emitting a gamma ray without changing mass
A proton capturing an electron to form a neutron
A heavy nucleus splitting into two smaller nuclei (Correct answer)
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 40: According to collision theory, a reaction occurs when molecules collide with:

Sufficient energy and proper orientation (Correct answer)
Any energy but only the correct orientation
Any energy at any orientation
Sufficient energy only, regardless of 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 41: 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 molar
1.0 molar
1.0 molal
2.0 molal (Correct answer)

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 42: What is the oxidation number of manganese (Mn) in the permanganate ion, MnO₄⁻?

+8
+7 (Correct answer)
+4
-1

Correct answer: +7

The sum of the oxidation numbers in a polyatomic ion must equal the charge of the ion. The charge on the permanganate ion is -1. The oxidation number of oxygen is typically -2. Let 'x' be the oxidation number of Mn. The equation is: x + 4(-2) = -1. Solving for x gives x - 8 = -1, so x = +7.

Question 43: A rigid 10.0 L container holds a mixture of nitrogen gas (N₂) and oxygen gas (O₂). The partial pressure of the nitrogen is 0.75 atm and the partial pressure of the oxygen is 0.25 atm. What is the total pressure inside the container?

0.50 atm
1.00 atm (Correct answer)
0.75 atm
Cannot be determined from the information given.

Correct answer: 1.00 atm

This scenario is an application of Dalton's Law of Partial Pressures. This law states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of the individual gases (P_total = P₁ + P₂ + ...). [10, 11, 21] In this case, P_total = P_N₂ + P_O₂ = 0.75 atm + 0.25 atm = 1.00 atm.

Question 44: The reaction between aqueous silver nitrate and aqueous sodium chloride produces solid silver chloride and aqueous sodium nitrate. How is this reaction best classified? AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

Decomposition
Synthesis
Single Displacement
Double Displacement (Precipitation) (Correct answer)

Correct answer: Double Displacement (Precipitation)

This reaction is a double displacement (or metathesis) reaction because the cations (Ag⁺ and Na⁺) and anions (NO₃⁻ and Cl⁻) from the two reactant compounds exchange partners to form two new compounds. Since one of the products, AgCl, is an insoluble solid (a precipitate), it is also specifically classified as a precipitation reaction.

Question 45: Which symbol represents the heat of a reaction measured at constant volume?

ΔS
ΔG
ΔH
ΔU (or ΔE) (Correct answer)

Correct answer: ΔU (or ΔE)

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

Question 46: Which of the following correctly expresses the number 0.0004075 in scientific notation?

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

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

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

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 48: Which of the following best describes the mass number of an atom?

The average mass of all isotopes of an element
The number of protons in the nucleus
The total number of electrons in an atom
The sum of the protons and neutrons in the nucleus (Correct answer)

Correct answer: The sum of the protons and neutrons in the nucleus

The mass number (A) of an atom represents the total count of protons and neutrons residing in its nucleus. It provides an approximate measure of the atom's mass in atomic mass units, as electrons contribute negligibly to the overall mass.

Question 49: 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 50: A beta particle emitted during beta-minus decay is identical to which particle?

A helium nucleus
A neutron
An electron (Correct answer)
A proton

Correct answer: An electron

A beta-minus particle is a high-energy electron emitted when a neutron in the nucleus converts to a proton.

Question 51: If the products of a reaction have higher enthalpy than the reactants, the ΔH for the reaction is:

Zero
Positive (Correct answer)
Negative
Cannot be determined

Correct answer: Positive

ΔH = H(products) – H(reactants); if products have higher enthalpy, ΔH is positive, indicating an endothermic reaction.

Question 52: What is the half-life of a radioactive isotope?

The time for half of the radioactive atoms in a sample to decay (Correct answer)
The time for all atoms to decay completely
The temperature at which decay rate doubles
The energy released when half the sample decays

Correct answer: The time for half of the radioactive atoms in a sample to decay

Half-life is the time required for exactly half of the radioactive nuclei in a sample to undergo decay.

Question 53: What type of bond is created when one atom donates an electron to another atom?

Ionic bond (Correct answer)
Metallic bond
Van der Waals bond
Covalent bond

Correct answer: Ionic bond

An ionic bond is formed when one atom completely transfers one or more electrons to another atom, resulting in the formation of oppositely charged ions. These cations (positive) and anions (negative) are then held together by strong electrostatic attraction.

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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