Basic Concepts of Chemistry - MCQ Test Basic Concepts of Chemistry - MCQ Test 1. What is the SI unit of mass? A. Gram B. Kilogram C. Meter D. Liter 2. Which of the following is a physical change? A. Burning of paper B. Dissolution of salt in water C. Rusting of iron D. Burning of wood 3. What is the atomic number of hydrogen? A. 1 B. 2 C. 3 D. 0 4. Which of the following is an example of a chemical change? A. Melting of ice B. Boiling of water C. Burning of paper D. Dissolution of sugar in water 5. Which of the following is a unit of temperature? A. Kelvin B. Newton C. Pascal D. Joule 6. The number of atoms in one mole of a substance is called: A. Atomic mass B. Avogadro's number C. Molecular mass D. Bohr's constant 7. What is the molar mass of water (H2O)? A. 18 g/mol B. 16 g/mol C. 2 g/mol D. 1 g/mol 8. The first law of thermodynamics is also called: A. Law of conservation of energy B. Boyle's Law C. Charles's Law D. Law of partial pressure 9. Which of the following is a pure substance? A. Air B. Salt C. Milk D. Soil 10. What is the chemical formula for methane? A. CH4 B. C2H6 C3H8 D. CH3 11. What is the term for a reaction that releases energy? A. Exothermic B. Endothermic C. Catalytic D. None of the above 12. What is the primary component of air? A. Oxygen B. Carbon Dioxide C. Nitrogen D. Argon 13. What is the molarity of a solution prepared by dissolving 2 moles of NaCl in 1 liter of solution? A. 1 M B. 2 M C. 0.5 M D. 0.2 M 14. Which of the following is a chemical property of water? A. It dissolves many ionic compounds B. It boils at 100°C C. It forms hydrogen bonds D. It dissociates into H+ and OH- ions 15. What is the atomic number of carbon? A. 6 B. 8 C. 12 D. 14 16. What is the symbol for gold? A. Au B. Ag C. Hg D. Fe 17. Which of the following is an acid? A. HCl B. NaOH C. NaCl D. Na2CO3 18. What is the main use of sodium bicarbonate (baking soda)? A. Antacid B. Food preservative C. Soap production D. All of the above 19. What is the chemical formula for sulfuric acid? A. H2SO4 B. H2O C. HNO3 D. NaOH 20. The law of constant proportions is also known as: A. Dalton's Law B. Avogadro's Law C. Proust's Law D. Boyle's Law Submit
