1
HESI A2 CHEMISTRY ACTUAL TEST
QUESTIONS AND ANSWERS 2026-27 LATEST
VERSION
1. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Nucleus
Answer: C
Rationale: Electrons carry a negative charge; protons are
positive, neutrons are neutral.
2. What is the atomic number of an element?
A. Number of protons
B. Number of neutrons
C. Mass number
D. Number of electrons only
Answer: A
Rationale: The atomic number equals the number of protons in
the nucleus of an atom.
3. Which element is a halogen?
A. Oxygen
B. Chlorine
,2
C. Sodium
D. Argon
Answer: B
Rationale: Halogens are Group 17 elements; chlorine is a
halogen.
4. What type of bond is formed by the transfer of electrons?
A. Covalent
B. Ionic
C. Metallic
D. Hydrogen
Answer: B
Rationale: Ionic bonds form when electrons are transferred
from one atom to another.
5. Which molecule is polar?
A. CO₂
B. O₂
C. H₂O
D. N₂
Answer: C
Rationale: Water has a bent shape, creating a polar molecule
with a dipole moment.
6. Calculate the molar mass of NaCl. (Na = 23, Cl = 35.5)
A. 58.5 g/mol
B. 50 g/mol
,3
C. 45 g/mol
D. 35.5 g/mol
Answer: A
Rationale: Na + Cl = 23 + 35.5 = 58.5 g/mol.
7. How many moles are in 36 g of water (H₂O)? (Molar mass =
18 g/mol)
A. 1 mol
B. 2 mol
C. 0.5 mol
D. 36 mol
Answer: B
Rationale: 36 ÷ 18 = 2 moles.
8. Which reaction represents a decomposition reaction?
A. A + B → AB
B. AB → A + B
C. AB + C → AC + B
D. A + O₂ → AO₂
Answer: B
Rationale: Decomposition reactions break a compound into
simpler substances.
9. What is the molarity of a solution with 5 moles of solute in 2
liters of solution?
A. 2.5 M
B. 0.4 M
, 4
C. 10 M
D. 1 M
Answer: A
Rationale: M = moles ÷ liters = 5 ÷ 2 = 2.5 M.
10. Which pH indicates a basic solution?
A. 2
B. 5
C. 7
D. 12
Answer: D
Rationale: pH > 7 is basic; pH < 7 is acidic.
11. Which of the following is an acid?
A. NaOH
B. HCl
C. KBr
D. CaCO₃
Answer: B
Rationale: HCl donates H⁺ ions in solution, making it an acid.
12. What is the formula weight of glucose (C₆H₁₂O₆)?
A. 180 g/mol
B. 162 g/mol
C. 150 g/mol
D. 200 g/mol
HESI A2 CHEMISTRY ACTUAL TEST
QUESTIONS AND ANSWERS 2026-27 LATEST
VERSION
1. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Nucleus
Answer: C
Rationale: Electrons carry a negative charge; protons are
positive, neutrons are neutral.
2. What is the atomic number of an element?
A. Number of protons
B. Number of neutrons
C. Mass number
D. Number of electrons only
Answer: A
Rationale: The atomic number equals the number of protons in
the nucleus of an atom.
3. Which element is a halogen?
A. Oxygen
B. Chlorine
,2
C. Sodium
D. Argon
Answer: B
Rationale: Halogens are Group 17 elements; chlorine is a
halogen.
4. What type of bond is formed by the transfer of electrons?
A. Covalent
B. Ionic
C. Metallic
D. Hydrogen
Answer: B
Rationale: Ionic bonds form when electrons are transferred
from one atom to another.
5. Which molecule is polar?
A. CO₂
B. O₂
C. H₂O
D. N₂
Answer: C
Rationale: Water has a bent shape, creating a polar molecule
with a dipole moment.
6. Calculate the molar mass of NaCl. (Na = 23, Cl = 35.5)
A. 58.5 g/mol
B. 50 g/mol
,3
C. 45 g/mol
D. 35.5 g/mol
Answer: A
Rationale: Na + Cl = 23 + 35.5 = 58.5 g/mol.
7. How many moles are in 36 g of water (H₂O)? (Molar mass =
18 g/mol)
A. 1 mol
B. 2 mol
C. 0.5 mol
D. 36 mol
Answer: B
Rationale: 36 ÷ 18 = 2 moles.
8. Which reaction represents a decomposition reaction?
A. A + B → AB
B. AB → A + B
C. AB + C → AC + B
D. A + O₂ → AO₂
Answer: B
Rationale: Decomposition reactions break a compound into
simpler substances.
9. What is the molarity of a solution with 5 moles of solute in 2
liters of solution?
A. 2.5 M
B. 0.4 M
, 4
C. 10 M
D. 1 M
Answer: A
Rationale: M = moles ÷ liters = 5 ÷ 2 = 2.5 M.
10. Which pH indicates a basic solution?
A. 2
B. 5
C. 7
D. 12
Answer: D
Rationale: pH > 7 is basic; pH < 7 is acidic.
11. Which of the following is an acid?
A. NaOH
B. HCl
C. KBr
D. CaCO₃
Answer: B
Rationale: HCl donates H⁺ ions in solution, making it an acid.
12. What is the formula weight of glucose (C₆H₁₂O₆)?
A. 180 g/mol
B. 162 g/mol
C. 150 g/mol
D. 200 g/mol
