Chemistry Past Questions And Answers
which of the following polymers is suitable for packaging and electrical insulation?
- A. polyamide
- B. polyethene
- C. polycarbonate
- D. polystyrene
The following factors would contribute to environmental pollution except
- A. production of ammonia
- B. manufacture of cement
- C. photosynthesis
- D. combustion
Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O2(g) → SO2(g) [S = 32; O = 16]
- A. 123g
- B. 139g
- C. 155g
- D. 182g
Nitrogen can best be obtained from a mixture of oxygen and nitrogen by passing the mixture over
- A) potassium hydroxide
- B) heated gold
- C) heated magnesium
- D) heated phosphorus
The fundamental difference between the three states of matter is the Options
- A) shape of their particles
- B) number of particles in each state
- C) shape of the container they occupy
- D) degree movement of their particles
Which of the following cells produce electrical energy from chemical reactions? l. Lead-acid battery ll. Dry cell III. Deniell cell IV Electrolytic cell
- A. l and ll only
- B. l, ll, and III only
- C. lll and IV only
- D. I and III only
A colourless, odourless liquid T, gives effervesce with sodium trioxocarbonate (IV) and a white precipitate with silver trioxonitrate (V) solution T is mose probably
- A. sodium chloride soluttion
- B. barium chloride solution
- C. dilute trioxonitrate (V) acid
- D. dilute hydroxide is unstable
The oxidation state of carbon in HCOOH is
- A. -1
- B. +2
- C. +3
- D. zero
Which of the following sugars is a product of the condensation of monosaccharides?
- A. galactose
- B. maltose
- C. glucose
- D. fructose
(a)(i) Draw the energy profile diagram for the reaction; H\(_{2(g)}\) + I\(_{2(g)}\) \(\to\) 2Hl\(_{(g)}\); \(\Delta\)H = –13 KJ mol\(^{-1}\)
(ii) If the concentration of HI\(_{(g)}\) increases from 0.000 to 0.002 mol dm\(^{-3}\) in 80 seconds, what is the rate of t reaction?
(b)(i)Give one use of each of the following compounds: I. NaHCO\(_{3}\); II. CaSO\(_{4}\); III. CaCO\(_{3}\).
(ii) State a drying agent that can be used for each of the following gases: I. SO\(_{2}\); II. HCI; Ill. NH\(_{3}\)
(c)(i) Write an equation for the complete combustion of carbon in oxygen.
(ii) Calculate the number moles of carbon (IV) oxide produced from the complete combustion of 2.5 g of carbon. [ C = 12.0, O = 16]
(iii) Mention one use of I. carbon (II) oxide; II. carbon (IV) oxide.
(d) An industrial raw material has the following composition by mass:
Iron = 28.1%; Chlorine = 35.7%; Water cf crystallization = 36.2%.
Calculate the formula for the material. [H = 1.00, O = 16.0, CI = 35.5, Fe = 56.0]
(e) Give one example of a (i) metal that is liquid at room temperature,
(ii) non-metal that is liquid room temperature.
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