Soap lather is an example of a colloid in which a?
- A. liquid is dispersed in gas
- B. solid is dispersed in liquid
- C. gas is dispersed in liquid
- D. liquid is despersed in liquid
90.0g of MgCI2 was placed in 50.0cm3 of water to give a saturated solubility of the salt is 8.0 mol dm3 at the same temperature, what is the mass of the salt left undissolved at the given temperature?
(Mg = 24, Cl = 35.5)
- A. 52.0g
- B. 58.5g
- C. 85.5g
- D. 88.5g
If an element X of an atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is?
- A. yzX + 10n → y - 1z + 1X
- B. yzX + 10n → y + 1zX
- C. yzX + 10n → yz + 1X
- D. yzX + 10n → y + 1z - 1X
Excess phosphorus was burnt in a gas jar and the residual gas passed successively over concentrated KOH solution and concentration H2SO4 before being collected in a flask. The gases collected are?
- A. carbon (IV) oxide, nitrogen and the rare gases
- B. nitrogen and the rare gases
- C. carbon (IV) oxide, nitrogen (IV) oxide and the rare gases
- D. carbon (IV) oxide
The soil around a battery manufacturing factory is likely to contain a high concentration of?
- A. Ca2+ salts
- B. Pb2+ salts
- C. Mg2+ salts
- D. Al3+ salts
Potassium tetraoxomanganate (VII) is often added to impure water to?
- A. reduce organic impurities
- B. reduce inorganic impurities
- C. destroy bacteria and algae
- D. remove permanent hardness
The property used in obtaining oxygen and nitrogen industrially from air is the?
- A. boiling point
- B. density
- C. rate of diffusion
- D. solubility
The line observed in the sample hydrogen spectrum are due to emission of?
- A. electrons from the atoms
- B. energy by proton transition
- C. energy by electron transition
- D. neutron from the atom
Which of the following electron configurations indicates an atom with the highest ionization energy?
- A. 2,8,7
- B. 2,8,8,1
- C. 2,8,8,2
- D. 2,8,8,7
A solid begins to melt when?
- A. constituent particles acquires a greater kinetic energy
- B. energy of vibration of particles of the solid is less than the intermolecular forces
- C. constituent particles acquires energy above the average kinetic energy
- D. energy of vibration of particles of the solid equals the intermolecular forces
If sulphur (IV) oxide and methane are released simultaneously at the opposite ends of a narrow tube, the rates of diffusion Rso2 and Rch4 will be in the ratio?
(S = 32, O = 16, C = 12, H = 1)
- A. 4:1
- B. 2:1
- C. 1:2
- D. 1:4
30cm3 of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C?
- A. 40.0 cm3
- B. 35.7 cm3
- C. 28.4 cm3
- D. 25.2 cm3
C3H8(g) + 502(g) → 4H2O + 3CO2(g). Form the equation above the volume of oxygen at s.t.p. required to burn 50cm3 of propane is?
- A. 250 cm3
- B. 150 cm3
- C. 100 cm 3
- D. 50 cm3
8.0 g of an element X react with an excess of copper (ll) tetraoxosulphate (lV) solution to deposit 21.3 g of copper. The correct equation for the reaction is?
(Cu = 64).
- A. X(s) + CuSO4(aq) → Cu(s) + XSO4(aq)
- B. X(s) + 2CuSO4(aq) → 2Cu(s) + X(SO4)2(aq)
- C. 2X(s) + CuSO4(aq) → Cu(s) + X2SO4(aq)
- D. 2X(s) + 3CuSO4(aq) → 3Cu(s) + X2(SO4)3(aq)
A given amount of gas occupies 10.0 dm3 at 4atm and 273°C. The number of moles of the gas present is?
(Molar volume of a gas at s.t.p. = 22.4 dm3)
- A. 0.89 mol
- B. 1.90 mol
- C. 3.80 mol
- D. 5.70 mol
A mixture of iron and sulphur can be separated by dissolving the mixture in?
- A. steam
- B. dilute hydrochloric acid
- C. dilute sodium hydroxide
- D. benzene
The addition of water to calcium oxide leads to?
- A. a physical change
- B. a chemical change
- C. the formation of a mixture
- D. an endothermic change