NH\(_3\)\(_{(g)}\) + HCl\(_{(g)}\) โ NH\(_4\)Cl\(_{(s)}\)
The entropy change in the system above is
- A. negative
- B. indeterminate
- C. positive
- D. zero
In which of the following reactions has the oxidation number of nitrogen increased?
- A. 2NO(g) + Br2(l) โ 2NOBr(l)
- B. 2NO(g) + O2(g) โ 2NO2(g)
- C. FeSO4(aq) + NO(g) โ Fe(NO)SO4(s)
- D. 2NO(g) + Cl2(g) โ 2NOCl(l)
As the concentration of an electrolyte reduces, the conductivity
- A. reduces to zero
- B. decreases
- C. increases
- D. is unaffected
When ฮH is negative, a reaction is said to be
- A. ionic
- B. reversible
- C. exothermic
- D. endothermic
3Cu(s) + 8HNO\(_3\)(aq) โ 3Cu(NO\(_3\))\(_2\)(aq) + 4H\(_2\)O(l) + 2NO(g)
In the equation above, copper is
- A. an electron acceptor
- B. a base
- C. an oxidizing agent
- D. a reducing agent
2SO\(_2\)(g) + O\(_2\)(g) โ 2SO\(_3\)(g)
ฮH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by?
- A. decreasing the temperature of the system
- B. Increase the pressure of the system
- C. The addition of a catalyst to the system
- D. Increasing the surface area of the vessel
C(s) + 2S(g) โ CS\(_2\)(g)
ฮH = +89 kJ mol-1
The chemical equation above implies that
- A. each of carbon and sulphur has 89 kJ of energy
- B. both carbon and sulphur contribute 89 kJ of energy
- C. 89 kJ of energy is released
- D. 89 kJ of energy is absorbed
Ethanoic acid is
- A. tribasic
- B. unionizeable
- C. monobasic
- D. dibasic
What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96 500 C mol-1]
- A. 32
- B. 8
- C. 4
- D. 16
Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises?
- A. The bonds in the reacting molecules are more readily broken
- B. The molecular collisions become more violent
- C. A lower proportion of the molecules has the necessary minimum energy to react
- D. The collision frequency of the molecules increase
A metal M displaces zinc from zinc chloride solution. This shows that
- A. M is more electronegative than zinc
- B. Zinc is above hydrogen in the series
- C. M is more electropositive than zinc
- D. Electrons flow from zinc to M
P(g) + Q(g) โ 3R(s) + S(g) ฮH is negative
Which of the following will increase the yield of R?
- A. Using a larger close vessel
- B. Increasing the temperature
- C. Removing some S
- D. Adding a positive catalyst
In which of the following reactions does reduction takes place
- A. Fe2+ - e- โ Fe3+
- B. 2O2- โO2 + 4e-
- C. Cr โ 2e- โ Cr2+
- D. 2H+ + 2e- โ H2
Phosphorus is stored under water to prevent it from
- A. Dehydrating
- B. Becoming inert
- C. Smelling
- D. Catching fire
The chemical used for coagulation in water purification is
- A. Aluminium tetraoxosulphate (VI)
- B. Copper tetraoxosulphate (VI)
- C. Sodium tetraoxosulphate (VI)
- D. Calcium tetraoxosulphate (VI)
Environmental pollution is worsened by the release from automobile exhausts of?
- A. Water vapour
- B. Steam
- C. Smoke
- D. Heavy metals
What is the decrease in volume of air when pyrogallol is shaken with 30.00cm\(^3\) of air ?
- A. 15.00cm3
- B. 6.30cm3
- C. 0.63cm3
- D. 0.06cm3
Pure solvents are obtained by
- A. Distillation
- B. Condensation
- C. Extraction
- D. Evaporation
Deliquescent substances are used for
- A. Cooling
- B. Wetting
- C. Melting
- D. Drying
The pollution from petroleum spillage in rivers and lakes can best be dispersed by
- A. Pouring detergents
- B. Passing of ships through the area
- C. Pouring organic solvents
- D. Evaporation
Which of the following statements is correct about the average kinetic energy of the molecules of a gas?
- A. It increase with increase in pressure
- B. It increase at constant temperature
- C. It increase with increase in temperature
- D. It increase with increase in volume