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
✓✗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
✓✗1.0 g of H2 has the same number of molecules as
- 28 g of N2
- 18 g of H2O
- 16 g of CO
- 14 g of N2
General
✓✗If the Avogadro number NA is changed from 6.022 × 1023 mol−1 to 6.022 × 1020 mol−1, this would change
- the ratio of elements to each other in a compound
- the definition of mass in units of grams
- the ratio of chemical species to each other in a balanced equation
- the mass of one mole of carbon
General
✓✗When 10 g of calcium carbonate is heated strongly, 5.6 g of calcium oxide is left. The mass of carbon dioxide evolved, as per the law of conservation of mass, is
- 5.6 g
- 4.4 g
- 10 g
- 15.6 g
General
✓✗The molecular mass of H2SO4 is (H = 1, S = 32, O = 16)
- 100 u
- 96 u
- 49 u
- 98 u
General
✓✗In an experiment, 10 mL of a 0.05 M solution of a chloride required 10 mL of a 0.1 M solution of AgNO3. The formula of the chloride is (X stands for the element other than chlorine)
- X2Cl
- XCl4
- XCl2
- X2Cl2
General
✓✗The volume of hydrogen at STP liberated when 2.4 g of magnesium reacts with excess dilute HCl is (Mg = 24)
- 1.12 L
- 22.4 L
- 2.24 L
- 4.48 L
General
✓✗The percentage of Se in peroxidase anhydrous enzyme is 0.5% by weight (atomic mass of Se = 78.4). The minimum molecular mass of peroxidase anhydrous enzyme is
- 1.568 × 103
- 15.68
- 1.568 × 104
- 2.136 × 104
General
✓✗If 0.5 mol of a substance has a mass of 32 g, its molar mass is
- 16 g mol−1
- 128 g mol−1
- 64 g mol−1
- 32 g mol−1
General
✓✗A hydrocarbon contains 80% carbon. Its empirical formula is
- CH4
- CH
- CH3
- CH2
General
✓✗In which state of matter do particles have the least freedom of movement?
- Gas
- Liquid
- All have equal freedom
- Solid
General
✓✗Which of the following concentration terms does NOT change with temperature?
- Mass per unit volume
- Normality
- Molarity
- Molality
General
✓✗The number of significant figures in 6.022 × 1023 is
- 27
- 4
- 3
- 23
General
✓✗The right option for the mass of CO2 produced by heating 20 g of 20% pure limestone is (atomic mass of Ca = 40) [CaCO3 → CaO + CO2, at 1200 K]
- 1.76 g
- 1.12 g
- 2.64 g
- 1.32 g