- 1. 1. In which of the following separation methods does chemical reaction occur?
A) Precipitation
B) Distillation
C) Chromatography
D) Sublimation
- 2. 2. The purity of a solid sample can best be determined by its :
A) Conductivity
B) Solubility
C) Melting point
D) Boiling points
- 3. 3. The constituent of lead pigment can be separated by:
A) Chromatography
B) Fractional crystallisation
C) Filtration
D) Fractional distillation
- 4. 4. Which of the following properties is not employed in the separation of a mixture?
A) Solubility
B) Boiling points
C) Densities
D) Molar masses
- 5. 5. Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?
A) Fractional distillation
B) Boiling off the ethanol
C) Fractional crystallisation
D) Filtration
- 6. 6. When a solid substance changes directly to a gas on heating without passing through the liquid state, the substance is said to have undergone:
A) Sublimation
B) Evaporation
C) Crystallisation
D) Melting
- 7. 7. Fractional distillation is used to separate:
A) Liquids with different boiling points
B) Substances which differ in their solubilities in a solvent
C) Gaseous, liquid or solid impurities from a mixture
D) An insoluble substance from a soluble substance
- 8. 8. A mixture of kerosene and water can be separated by:
A) Distillation
B) Separating funnel
C) Crystallisation
D) Sublimation
- 9. 9. What is the mass number of an element if its atom contains 10 protons, 10 electrons, and 12 neutrons?
A) 22
B) 32
C) 20
D) 10
- 10. 10. The electronic configuration of an atom is 2,8,8,2. The atomic number of the element is, therefore ----------:
A) Z15
B) 18
C) 20
D) 10
- 11. 11. What is the percentage by mass of sodium in sodium hydroxide? (Na = 23, O = 16, H = 1)
A) 57.5%
B) 42.5%
C) 73.0%
D) 40.4%
- 12. 12. What is the percentage by mass of sulphur in aluminium tetraoxosulphate (VI), Al2(SO4)_3. ( Al = 27, S = 32, O = 16)
A) 28.07%
B) 42.66%
C) 21.33%
D) 14.71%
- 13. 13. How many electrons are in the ion F, If 19 F has neutron of 8?
A) 9
B) 8
C) 11
D) 27
- 14. 14. Calculate the formula mass of tri lead tetraoxide Pb3O4 (Pb= 207, O = 16)
A) 621
B) 586
C) 865
D) 685
- 15. 15. Calculate the formula mass of tetraoxosulphate (VI) acid H2SO4 (S= 32, H = 1, O = 16)
A) 102
B) 64
C) 40
D) 98
- 16. 16. What is the molecular mass of calcium trioxonitrate (V) Ca (NO3)_2 (Ca = 40, N = 14, O = 16)
A) 160
B) 146
C) 104
D) 164
- 17. 17. One of the following is the Avogadro's constant:
A) 6.02 × 10-23
B) 6.02 × 1032
C) 6.02 × 1023
D) 6.02 × 10-32
- 18. 18. The relative atomic mass of any element in grams contains -------- mole of atom
A) 3
B) 4
C) 1
D) 2
- 19. 19. The sum of the relative atomic masses of all the atoms in one molecule of the substance is referred to as ----------
A) Relative atomic mass
B) Relative molecular mass
C) Relative avogadro's abundance
D) Relative abundance
- 20. 20. The electronic configuration of an atom is: 2, 8, 7. What element is it?
A) Potassium
B) Sulphur
C) Argon
D) Chlorine
- 21. The shape of the p-orbitals is -------
A) Dumb-bell
B) Longitudinal symmetrical
C) Spherical
D) Oval
- 22. --------------- states that electrons are distributed among orbitals of the same subshell singly before pairing occurs.
A) Pauli's principle
B) Aufbau principle
C) Hund's rule
D) Azimuthal rule
- 23. The maximum number of electrons which can occupy the energy sub-level "f" is ......
A) 8
B) 10
C) 14
D) 6
- 24. When an atom gains an electron, it becomes ........
A) Chemically inactive
B) Cation
C) Complex ion
D) Negatively charged
- 25. The shape of the S-orbitals is .......
A) Circular
B) Longitudinally symmetrical
C) Dumb-bell
D) Spherically symmetrical
- 26. The principal quantum number "k" takes maximum of ....
A) 2 electrons
B) 8 electrons
C) 10 electrons
D) 6 electrons
- 27. No two electrons in the same atom can have the same values for all four quantum numbers . This is the ..........
A) Azimuthal
B) Hund's rule
C) Aufbau principle
D) Pauli exclusive principle
- 28. The maximum number of electrons which can occupy the "s" energy sub-level is .........
A) 6 electrons
B) 8 electrons
C) 32 electrons
D) 2 electrons
- 29. One of the following is a diatomic element.
A) Ozone
B) Phosphorus
C) Nitrogen
D) Sulphur
- 30. The smallest particle which can participate in chemical reactions is know as......
A) Molecule
B) Compound
C) Matter
D) Atom
- 31. What is the molar mass of water (H2O)?
A) 24 g/mol
B) 26 g/mol
C) 22 g/mol
D) 18 g/mol
- 32. How many moles are there in 50 grams of carbon dioxide (CO2)?
A) 2 moles
B) 1.5 moles
C) 0.5 mole
D) 1 mole
- 33. Avogadro's constant (NA) represents the number of:
A) Electrons in one mole of a substance
B) Molecules in one mole of a substance
C) Ions in one mole of a substance
D) Atoms in one mole of a substance
- 34. What is the percentage of carbon in carbon dioxide (CO2)?
A) 27.27%
B) 12%
C) 44%
D) 32%
- 35. The molecular formula of a compound represents the:
A) Simplest whole-number ratio of atoms in the compound
B) Molar mass of the compound
C) Actual number of atoms in the compound
D) Empirical formula of the compound
- 36. What is the molar mass of sulfuric acid (H2SO4)?
A) 98.1 g/mol
B) 98 g/mol
C) 78 g/mol
D) 62 g/mol
- 37. What is the empirical formula of a compound that contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen?
A) C4H8O4
B) C3H6O3
C) CH2O
D) C2H4O2
- 38. The molar mass of a compound is 180 g/mol, and its empirical formula is CH2O. What is its molecular formula?
A) C2H4O2
B) C3H6O3
C) C6H12O6
D) C4H8O4
- 39. The empirical formula of a compound represents the:
A) Molecular formula of the compound
B) Molar mass of the compound
C) Actual number of atoms in the compound
D) Simplest whole-number ratio of atoms in the compound
- 40. What is the molar volume of a gas at standard temperature and pressure (STP)?
A) 24.0 L/mol
B) 26.2 L/mol
C) 28.0 L/mol
D) 22.4 L/mol
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