In countries where the temperature fall below 273k, salt always spilled on the road in order to
- A. increase the boiling point
- B. increase the density of the ice
- C. make the ice impure
- D. reduce the freezing point of ice
Alloys are best prepared by
- A. electroplating
- B. Arc-welding
- C. reducing and mixture of their metallic
- D. cooking a molten of the metals
Electronic configuration of an element 13 in the subsidiary energy level is
- A. \( 1s^2 2s^2 2p^6 3s^2 3p^1 \)
- B. \( 1s^22s^2 2p^4 3p^1 3s^1 \)
- C. \( 1s^2 2s^2 2p^6 3s^2 3p^3 \)
- D. \( 1s^1 2s^2 2p^6 3s^2 3p^4 \)
Which of the following gives a precipitation when treated with NaOH Solution?
- A. AlCl3
- B. NH4Cl
- C. Na2CO3
- D. CH3COONa
PCL5(g)= PCL3(g) + Cl2(g)
In the reaction above, a decrease in pressure will
- A. Decelerate the reaction
- B. Increase yield of Pcl3
- C. Increase the yield of Pcl5
- D. Accurate the reaction
According to the kinetic theory an absence in temperature causes the kinetic energy of particles to
- A. decrease
- B. increase
- C. remain constant
- D. be zero
A difference between chemical and physical change is that in a chemical change
- A. oxygen is consumed
- B. heat is supplied
- C. the reversible process occurs
- D. a new substance is formed
The furring of kettles is caused by the presence of what compound in water?
- A. calcium tetraoxosulphate (IV)
- B. calcium hydrogentrioxocarbonate (IV)
- C. calcium hydroxide
- D. calcium trioxocarbonate (IV)
Which of the following results in the fall of acid rain?
- A. oxide of lead
- B. particulate matter
- C. oxides of sulphur
- D. gaseous hydrocarbon
Detergents are manufactured with straight hydrocarbon chains, is to make them
- A. soluble
- B. biodegradable
- C. cheaper
- D. foamy
NH3(g) + HCl(s) → NH 4Cl (s)
The entropy change in the system above is
- A. positive
- B. zero
- C. negative
- D. intermediate
When sugar is dissolve in tea, the reaction is accomplished by?
- A. positive change
- B. negative entropy change
- C. no entropy change
- D. a minimum entropy change
The elements that belong to the third period of periodic table are
- A. Li, Be, Al and D
- B. Na, P, O and Cl
- C. B, C, N, and O
- D. Na, Mg, S and Ar
A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, Find the molecular formula [H = 1, C = 12, O = 16)
- A. CH2O
- B. C3H6O3
- C. C6H12O6
- D. C6H12O3
What volume of 0.5mldm3 H2SO4 will exactly neutralize 20cm3 of 0.1moldm3 NaOH Solution?
- A. 2.0cm3
- B. 5.0cm3
- C. 6.8cm3
- D. 8.3cm3
The energy value of petrol can be determined by
- A. Bomb calorimeter
- B. Catalytic cracker
- C. Fractionating column
- D. Thermometer
The basic particles from which matter could be made up of are as follow, except?
- A. Salt
- B. Atom
- C. Ion
- D. Molecule
\(Cu_2S_{(s)}+ O_{2(g)} = 2CU_{(s)} + SO_{2(g)}\).
In the above reaction, the oxidation number of Cu changes from ___ to _______?
- A. +1 to 0
- B. 0 to +2
- C. +2 to +1
- D. 0 to +1
All these are electromagnetic waves except
- A. White light
- B. Photon
- C. X-ray
- D. Infrared