General
✓✗Concentrated nitric acid used in the laboratory is 68% HNO3 by mass, with a density of 1.504 g mL−1. The molarity of the acid is about (H = 1, N = 14, O = 16)
- 16.2 M
- 32.4 M
- 10.8 M
- 6.8 M
General
✓✗The molarity of a solution containing 4 g of NaOH in 500 mL of solution is (molar mass of NaOH = 40 g mol−1)
- 0.4 M
- 0.2 M
- 0.1 M
- 2 M
General
✓✗How many litres of air at STP (21% oxygen by volume) are required for complete combustion of 1 mol of propane?
- 112 L
- 533 L
- 107 L
- 224 L
General
✓✗In the reaction 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l), when 1 mol of ammonia and 1 mol of O2 are made to react to completion,
- all the oxygen will be consumed
- 1.0 mol of H2O is produced
- all the ammonia will be consumed
- 1.0 mol of NO will be produced
General
✓✗The specific volume of a cylindrical virus particle is 6.02 × 10−2 cm3 g−1, and its radius and length are 7 Å and 10 Å respectively. If NA = 6.02 × 1023 mol−1, the molar mass of the virus is
- 1.54 × 104 kg mol−1
- 3.08 × 104 kg mol−1
- 15.4 kg mol−1
- 3.08 × 103 kg mol−1
General
✓✗The number of chloride ions in 0.1 mol of CaCl2 is
- 6.022 × 1023
- 1.204 × 1023
- 6.022 × 1022
- 3.011 × 1022
General
✓✗Two students measured a mass of 3.00 g. Student A got 2.95 g and 2.93 g; student B got 3.01 g and 2.99 g. Which statement is correct?
- B is both precise and accurate
- A is both precise and accurate
- A is accurate but not precise
- B is precise but not accurate
General
✓✗An organic compound on combustion gave 0.44 g of CO2 and 0.18 g of H2O from 0.30 g of the compound containing C, H and O. The empirical formula is
- CH4O
- CH2O
- C2H4O
- CHO
General
✓✗10 mL of a gaseous hydrocarbon needs 30 mL of oxygen for complete combustion and gives 20 mL of carbon dioxide, all volumes at the same temperature and pressure. The hydrocarbon is
- C2H6
- C2H4
- C2H2
- C3H6
General
✓✗A 2.0 g mixture of NaCl and KCl, on treatment with excess AgNO3, gave 4.3 g of AgCl. The mass of NaCl in the mixture is about (Na = 23, K = 39, Cl = 35.5, Ag = 108)
- 1.0 g
- 0.5 g
- 1.15 g
- 0.85 g
General
✓✗The mass of 11.2 L of a gas at STP is 14 g. The molar mass of the gas is
- 56 g mol−1
- 14 g mol−1
- 28 g mol−1
- 7 g mol−1
General
✓✗The percentage of hydrogen in water is about (H = 1, O = 16)
- 88.9%
- 11.1%
- 33.3%
- 5.6%
General
✓✗Dalton's atomic theory could NOT explain which of the following?
- Law of conservation of mass
- Law of gaseous volumes
- Law of constant proportions
- Law of multiple proportions
General
✓✗The mass of oxygen required for the complete combustion of 2.8 kg of ethylene is
- 96 kg
- 9.6 kg
- 2.8 kg
- 6.4 kg
General
✓✗The smallest particle of a substance that can exist independently and shows all its properties is
- a nucleus
- a molecule
- an electron
- an atom