HESI A2
HESI A2 Chemistry Practice Questions
1. To the nearest whole number, what is the mass of one mole of hydrogen iodide?
- A. 2 g/mol
- B. 58 g/mol
- C. 87 g/mol
- D. 128 g/mol
Correct answer: C
Rationale: The molar mass of hydrogen iodide (HI) is the sum of the atomic masses of its constituent elements. Hydrogen (H) has a molar mass of approximately 1 g/mol, and iodine (I) has a molar mass of about 127 g/mol. Thus, the molar mass of hydrogen iodide (HI) is approximately 1 + 127 = 128 g/mol. Rounding to the nearest whole number, the molar mass of hydrogen iodide is 128 g/mol, which is closest to choice C. Choice A (2 g/mol) is too low and does not reflect the correct molar mass of hydrogen iodide. Choice B (58 g/mol) is significantly lower than the actual molar mass. Choice D (128 g/mol) matches the calculated molar mass but is not the nearest whole number as requested.
2. Which factor does not affect the reaction rate of a chemical reaction?
- A. Temperature
- B. Surface area
- C. Concentration of reactants
- D. Color of the reactants
Correct answer: D
Rationale: The color of reactants is not a factor that affects the rate of a chemical reaction. Temperature, surface area, and concentration of reactants are known factors that influence the reaction rate. Temperature plays a significant role in altering the reaction rate by affecting the kinetic energy of molecules. Surface area impacts the rate by providing more area for collisions to occur. Concentration affects the frequency of effective collisions. On the other hand, the color of reactants is a physical property that does not directly affect the speed of a chemical reaction.
3. You contain two odorous gases in vials with porous plugs. Gas A has twice the mass of Gas B. Which observation is most likely?
- A. You will smell Gas A before you smell Gas B.
- B. You will smell Gas B before you smell Gas A.
- C. You will smell Gas A but not Gas B.
- D. You will smell Gas B but not Gas A.
Correct answer: A
Rationale: The rate of effusion of a gas is inversely proportional to the square root of its molar mass. Since Gas A has twice the mass of Gas B, Gas A will effuse more slowly than Gas B. Therefore, you will likely smell Gas A before you smell Gas B as Gas A will escape and diffuse through the porous plug at a slower rate compared to Gas B. Choice A is correct because Gas A, with its higher molar mass, will take longer to effuse through the porous plug, causing you to smell it first. Choices B, C, and D are incorrect as they do not consider the relationship between molar mass and effusion rate.
4. What are the two types of chemical bonding?
- A. Covalent & hydrogen
- B. Ionic & covalent
- C. Ionic & hydrogen
- D. Covalent & metallic
Correct answer: B
Rationale: The correct answer is B: Ionic & covalent. Ionic bonding involves the transfer of electrons between atoms, resulting in the formation of positive and negative ions attracted to each other. Covalent bonding involves the sharing of electrons between atoms to achieve a stable electron configuration. Choice A is incorrect as hydrogen bonding is a type of intermolecular force, not a primary type of chemical bonding. Choice C is incorrect as hydrogen bonding is not a primary type of chemical bonding. Choice D is incorrect as metallic bonding involves the sharing of electrons in a 'sea of electrons' within a metal lattice, not covalent bonding.
5. What are the three types of radiation?
- A. Alpha, beta, gamma
- B. Alpha, beta, delta
- C. Gamma, delta, epsilon
- D. Beta, gamma, epsilon
Correct answer: A
Rationale: The correct answer is Alpha, beta, gamma. Alpha radiation consists of helium nuclei, beta radiation comprises electrons or positrons, and gamma radiation is high-energy electromagnetic radiation. Choice B, delta, is incorrect as delta is not a type of radiation. Choice C, gamma, delta, epsilon, and Choice D, beta, gamma, epsilon, are incorrect as they do not include the three standard types of radiation.
Similar Questions
Access More Features
HESI A2 Basic
$99/ 30 days
- 3,000 Questions with answers
- 30 days access
HESI A2 Premium
$149.99/ 90 days
- Actual HESI A2 Questions
- 3,000 questions with answers
- 90 days access