What properties of duralumin make it more useful than its constituent metals?
- A. It is heavy with a high melting point
- B. It is malleable and has high density
- C. It is strong and light
- D. It is hard and ductile
Hydrogen is used in oxy-hydrogen flames for melting metals because it
- A. evolves a lot of heat when burnt
- B. combines explosively with oxygen
- C. is a very light gas
- D. is a rocket fuel
A pair of compounds that can be used to generate a gas which has physiological effect on human beings is
- A. sodium trioxonitrate (V) and calcium chloride
- B. sodium dioxonitrate (III) and ammonium chloride
- C. sodium trioxonitrate (V) and ammonium chloride
- D. sodium dioxonitrate (III) and potassium chloride
The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is
- A. Na2SO4
- B. Na2SO3
- C. Na2S
- D. Na2CO3
Chlorine, bromine and iodine resemble one another in that they?
- A. dissolve in alkalis
- B. react violently with hydrogen without heating
- C. are liquids
- D. displace one another from solutions of their salts
The gas that will form a white precipitate with acidified silver trioxonitrate (v) is
- A. NH3
- B. SO2
- C. CO2
- D. HCL
Which of the following statement is true of the electrochemical series?
- A. Electropositivity of metals increase down the series
- B. Electropositivity of non-metals decrease down the series
- C. Electronegativity of non-metals decrease down the series
- D. Electropositivity of metals decreases down the series
RS(aq) + HF(aq) โ RF(s) + HS(aq)
ฮH = -65.7 kj mol(-1).
From the equation above, it can be deduced that
- A. the heat content of the reactants is lower than that of the products
- B. the heat content of the reactants is higher than that of the products
- C. the reaction is slow
- D. a large amount of heat is absorbed
When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes?
- A. X/4 g
- B. X/2 g
- C. 2X g
- D. 4X g
X + Y โ Z. The rate equation for the chemical reaction above is \(\frac{-ฮx}{ฮt}\) = K[X]\(^2\)[Y].
The overall order of the reaction is?
- A. 0.0
- B. 1.0
- C. 2.0
- D. 3.09
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
[ F = 96 5000 C mol-1 ]
- A. 24 125 coulombs
- B. 48 250 coulombs
- C. 72 375 coulombs
- D. 96 500 coulombs
N2O4(g) โ 2NO2(g). Increase in total pressure of the equilibrium reaction above will
- A. produce more of NO2(g) in the mixture
- B. convert all of N2O4(g) to NO2(g)
- C. have no effect on the concentrations of NO2(g)and N2O4(g)
- D. produce more of N2O4(g) in the mixture
2SO2(g) + O2(g) โ 2SO3(g). In the chemical reaction above, the substance that will increase the rate of production of sulphur (VI) oxide is
- A. manganese (IV) oxide
- B. finely divided iron
- C. vanadium (V) oxide
- D. nickel
The entropy and enthalpy of a system are a measure of
- A. degree of disorderlinesss and heat content respectively
- B. heat content and degree of disorderliness respectively
- C. heat content of a system only
- D. degree of disorderliness only
The solubility product of Cu(IO3)2 is 1.08 * 10-7. Assuming that neither ions react appreciable with water to form H+ and OH–, what is the solubility of this salt?
- A. 2.7 * 10-8 mol dm-3
- B. 9.0 * 10-8 mol dm-3
- C. 3.0 * 10-3 mol dm-3
- D. 9.0 * 10-3 mol dm-3
The solution with the lowest pH value is
- A. 5 ml of (m/10) HCL
- B. 10 ml of (m/10) HCL
- C. 15 ml of (m/5) HCL
- D. 20 ml of (m/8) HCL
What is observed when aqueous solutions of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together?
- A. A white precipitate is formed
- B. A green precipitate is formed
- C. The mixture remains colourless
- D. The mixture turns reddish brown
The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is
- A. CO, CO2 and SO2
- B. CO, HCL and SO2
- C. CO, CO2 and HCL
- D. SO2, CO2 and HCL
The correct order of increasing oxidation number of the transition metal ions for the compounds K2Cr2O7, V2O5 and KMnO4 is
- A. V2O5 < K2Cr2O7 < KMnO4
- B. K2Cr2O7 < KMnO4 < V2O5
- C. KMnO4 < K2Cr2O7 < V2O5
- D. KMnO4 < V2O5 < K2Cr2O7
0.25 mole of hydrogen chloride was dissolved in distilled water and the volume made up of 0.50 dm3. If 15.0 cm3 of the solution requires 12.50 cm3 of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution
- A. 0.30 mol dm3
- B. 0.40 mol dm3
- C. 0.50 mol dm3
- D. 0.60 mol dm3
Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond?
- A. HF(g)
- B. NH3(g)
- C. CH4(g)
- D. HCl(g)