Chemistry Past Questions And Answers
In what way is equilibrium constant for the forward reaction related to that of the reverse reaction?
- A) The addition of the two is expected to be one
- B) The product of two is expected to be one
- C) The two equilibrium constants are identical
- D) The product of the two is always greater than one
Which of the statements about gases is not correct?
- A. Gases have low densities compared to solids and liquids of equal mass.
- B. The total kinetic energy of the gas is not affected by collision
- C. Molecules of the gas are in constant motion
- D. Gases are highly soluble in water at high temperatures
The reduction half equation of the following reaction is:
\(Zn_{(s)} + CuSO_{4(aq)} → ZnSO_{4(aq)} + Cu_{(s)}\)
- A. \(Zn_{(s)} → Zn^{2+}_{(aq)} + 2e^-\)
- B. \(CuSO_{4(s)} + H_2O_{(l)}\) → \(Cu^{2+}_{(aq)}\) + \(SO_{4(aq)}^{2-}\)
- C. \(Cu^{2+}_{(aq)} + 2e^- → Cu_{(s)}\)
- D. \(Cu^{2+}_{(aq)} + e^- → Cu_{(s)}\)
Which of the following pH values is likely to be that of a slightly alkaline system?
- A) 2
- B) 5
- C) 7
- D) 8
In which of the following will hydrogen form ionic compound?
- A. HCL
- B. NaH
- C. NH3
- D. CH4
The condition required for corrosion to take place is the presence of
- A) Oxygen and Carbon (IV) oxide
- B) Water and Oxygen
- C) Water and Carbon (IV) oxide and Oxygen
- D) Water and Carbon (IV) oxide
(a) List two substances that can be used in the laboratory to
(i) dry hydrogen;
(ii) remove carbon (IV) oxide from a sample of air;
(iii) convert hot copper (II) oxide to copper;
(iv) prepare zinc chloride by the action of dilute HCI.
(b)(i) Name two alloys which contain lead.
(ii) State and explain what is observed on bubbling H\(_2\)S into a solution of Pb(NO)\(_2\).
(iii) A metal M exists as a silvery white solid at temperatures above 18°C and as a grey solid below 18°C.
I. name the phenomenon exhibited by M.
II. What term is used to describe the temperature given as 18°C in this case?
(c)(i) Write an equation for the action of heat on each of the following compounds:
I. AgNO\(_3\)
II. (NH4)\(_2\)CO\(_3\).
(ii) Copy and complete the table below
Metal | Name of main ore | Method of extraction | One major use Haematite |
— | Haematite | — | — |
— | — | Electrolysis of molten oxide | — |
Which of the following acids from normal salt only?
- A. Tetraoxosulphate (IV) acid
- B. Tetraoxophosphate (V) acid
- C. Trioxonitrate (V) acid
- D. Trioxosulphate (IV) acid
100.0g of KClO3 was added to 40.0 cm3 of water to give a saturated solution at 298K. If the solubility of the salt is 20.0 mol dm?3 at 298K, what percentage of the salt is left undisolved? [K = 39, Cl = 35.5, O = 16]
- A) 80%
- B) 60%
- C) 5%
- D) 2%
The furring of kettles is caused by the presence in water of _______
- A) calcium trioxocarbonate (IV)
- B) calcium tetraoxosulphate (VI)
- C) calcium hydroxide
- D) calcium hydrogentrioxocarbonate (IV)