Check Questions 1 – 20 here
22. Which of the following substances is a mixture?
A. Granulated sugar
C. Sodium chloride
D. Iron filings.
23. The atomic numbers of two elements X and Y are 12 and 9 respectively. The bond in the compound formed between the two elements is?
24. In the purification of town water supply, alum is used principally to:
A. kill bacteria.
B. control the pH of water.
C. improve the taste of the water.
D. coagulate small panicles of mud.
25. An increase in temperature causes an increase in the pressure and the _____
A. average velocity of the molecules.
B. number of collisions between the molecules.
C. density of the molecules.
D. free mean path between each molecule and others.
26. The energy change accompanying the addition of an electron to a gaseous atom is called:
A. first ionization energy.
B. second ionization energy:
C. electron affinity.
27. An eruption polluted an environment with a gas suspected to be H2S, a poisonous gas. A rescue team should spray the environment with:
B. moist SO
C. acidified KMnO4 and water
D. water, acidified KMnO4 and oxygen.
28. The atomic number of Cesium is 55 and its atomic mass is 133. The nucleus of the Cesium atom therefore contains:
A. 78 protons and 55 electrons.
B. 55 protons and 78 neutrons.
C. 55 neutrons and 78 electrons.
D. 78 neutron and 55 neutrons.
29. Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is a noble gas?
30. If ZnO dissolves in sodium hydroxide and mineral acid solutions to give soluble products in each case, ZnO is therefore referred to as:
A. an allotropic acid.
B. an amphoteric
C. a peroxide.
D. a dioxide.
31. Chromatography is used to separate components of mixtures which differ in their rates of
32. Which of the following is an example of a chemical change?
A. Dissolution of salt in water.
B. Rusting of iron.
C. Melting of ice.
D. Separating a mixture by distillation.
33. The number of Hydrogen ions in 4.9g of tetraoxosulphate (V) acid is
A. 3.01 x 1022
B. 6.02 x 1022
C. 3.01 x 1023
D. 6.02 x 1023
[S = 32, O = 16, H = 1, NA = 6.02 x 1023]
34. What volume of oxygen will remain after reacting 8cm3 of hydrogen with 20cm3of oxygen?
35. A gas sample with an initial volume of 3.25dm3 is heated and allowed to expand to 9.75dm3 at constant pressure. What is the ratio of the final absolute temperature to the initial absolute temperature?
36. Two cylinders A and B each contain 30cm3 of oxygen and nitrogen respectively at the same temperature and pressure. If there are 5.0 moles of nitrogen, then the mass of oxygen is
37. A liquid begins to boil when______
A. its vapour pressure is equal to the vapour pressure of its Solid at the given pressure.
B. molecules stall escaping from its surface.
C. its vapour pressure equals the atmospheric pressure.
D. its volume is slightly increased.
38. A particle that contains 8 protons, 9 neutrons and 7 electrons could be written as
39. Which of the letters indicate an alkaline metal and a noble gas respectively?
A. M and E
B. G and E
C. R and L
D. G and L.
40. Which letter represents a non-metal that is a solid at room temperature?
Check Questions 1 – 20 here