JUPEB Chemistry
Past Questions
16+ verified Chemistry past questions for JUPEB. Step-by-step worked answers in 5 Nigerian languages.
Chemistry topics (2)
Sample Chemistry past questions
1. Number of electrons in O²⁻.
- A. 6
- B. 8
- C. 10
- D. 16
Answer: C
2. Functional group of carboxylic acids.
- A. —OH
- B. —CHO
- C. —COOH
- D. —NH₂
Answer: C
3. The number of moles in 36 g of water (H₂O, M=18) is:
- A. 1
- B. 2
- C. 3
- D. 0.5
Answer: B
4. Which is an alkali?
- A. HCl
- B. NaOH
- C. H₂SO₄
- D. CO₂
Answer: B
5. The bonding in NaCl is:
- A. Covalent
- B. Ionic
- C. Metallic
- D. Hydrogen
Answer: B
6. The most abundant gas in the atmosphere is:
- A. Oxygen
- B. Nitrogen
- C. Carbon dioxide
- D. Argon
Answer: B
7. Isotopes differ in the number of:
- A. Protons
- B. Electrons
- C. Neutrons
- D. Charges
Answer: C
8. The atomic number of an element is the number of:
- A. Neutrons
- B. Protons
- C. Electrons in outer shell
- D. Protons + neutrons
Answer: B
AI Explanation
Atomic number Z = number of protons. It uniquely identifies an element.
9. Which is a covalent compound?
- A. NaCl
- B. MgO
- C. CO₂
- D. KCl
Answer: C
AI Explanation
CO₂ shares electrons between C and O (covalent). NaCl/MgO/KCl are ionic.
10. Avogadro's number is approximately:
- A. 6.022 × 10²³
- B. 6.022 × 10²²
- C. 9.81 × 10²³
- D. 3 × 10⁸
Answer: A
AI Explanation
Avogadro's number = 6.022 × 10²³ entities per mole.
11. What is the empirical formula of hydrogen peroxide (H₂O₂)?
- A. HO
- B. H₂O
- C. H₂O₂
- D. OH₂
Answer: A
AI Explanation
Empirical formula = simplest integer ratio. H₂O₂ simplifies to HO (1:1 ratio).
12. Which is an organic compound?
- A. NaCl
- B. CH₄
- C. H₂O
- D. MgO
Answer: B
AI Explanation
Organic compounds contain carbon (and usually hydrogen). CH₄ (methane) is the simplest organic compound.
13. Which acid is present in vinegar?
- A. Sulphuric acid
- B. Acetic acid
- C. Hydrochloric acid
- D. Nitric acid
Answer: B
AI Explanation
Vinegar contains about 4–8% acetic acid (CH₃COOH).
14. Reduction is the:
- A. Loss of electrons
- B. Gain of electrons
- C. Loss of protons
- D. Gain of mass
Answer: B
AI Explanation
Reduction is gain of electrons (RIG — Reduction Is Gain). Oxidation is loss (OIL).
15. Which element forms the most compounds?
- A. Hydrogen
- B. Carbon
- C. Oxygen
- D. Nitrogen
Answer: B
AI Explanation
Carbon forms millions of compounds due to catenation (bonding to itself) and tetravalency — basis of organic chemistry.
16. What is the chemical formula of water?
- A. H₂O
- B. HO
- C. H₂O₂
- D. OH
Answer: A
AI Explanation
Water = H₂O (two hydrogen atoms covalently bonded to one oxygen).
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