30cm³ pf hydrogen at s.t.p combine with 20cm³ of oxygen to form steam according to the following equation 2H_2(g) + O_2(g) → 2H₂O_(g). Calculate the total volume of the gaseous mixture at the end of the reaction

A. 50cm³

B. 35cm³

C. 30cm³

D. 25cm³

An exothermic reaction is one which involves

A. attainment of dynamic equilibrium

B. loss of heat to the surrounding

C. evolution of gas as it proceeds

D. positive change in value of enthalpy

Which of the following is an acid salt?

A. NH₄CI

B. MgSO₄ 7H₂O

C. CH₃COONa

D. NaHCO₃

Which of the following compounds dissolves in water to form a solution with pH below 7?

A. Sodium tetraoxosulphate (VI)

B. Potassium hydroxide

C. Ammonium chloride

D. Sodium trioxocarbonate (IV)

If the solubility of KHCO₃ is 0.40 mole dm^{-3 at room temperature , calculate the mass of KHCO₃ in 100dm3 of the solution at this temperature. [KHCO₃ = 100hmol]}

A. 4.0g

B. 10.0g

C. 40.0g

D. 100.0g

The property of calcium chloride which makes it useful as a drying agent is that it is

A. ionic

B. deliquescent

C. a strong electrolyte

D. a normal salt

Which of the following lowers the activation energy of a chemical reaction?

A. Freezing mixture

B. Reducing agent

C. Water

D. Catalyst

Consider the reaction represented by the following equation: H_2(g) + 1_2(g) → 2HI_(g). The number of effective collisions of molecules of the reactants decreases as

A. the temperature is raised

B. the pressure increased

C. the volume of the system is increased

D. a catalysty is intoduced into the system

What will be the effect of increase in pressure on the following system at equilibrium? 2NH_2(g) N_2(g) + 3H_2(g)

A. Activation energy will decrease

B. the forward reaction will be favoured

C. the concentration of ammonia will increase

D. the reaction will go to completion

Which of the following is not correct about oxidation number convention? The oxidation number of a/an

A. element in the free state is zero

B. monatomic ion is equal to its charge

C. alkali meta like sodium in its compounds is + 1

D. atom of a diatomic molecules is + 2