Chemistry Past Questions and Answers

If an element X of an atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is?

A ^y_zX + ¹₀n â†’ ^{y - 1}_{z + 1}X
B ^y_zX + ¹₀n → ^{y + 1}_zX
C ^y_zX + ¹₀n â†’ ^y_{z + 1}X
D ^y_zX + ¹₀n â†’ ^{y + 1}_{z - 1}X

Question 17:

90.0g of MgCI₂ was placed in 50.0cm³ of water to give a saturated solubility of the salt is 8.0 mol dm³ at the same temperature, what is the mass of the salt left undissolved at the given temperature?
(Mg = 24, Cl = 35.5)

A 52.0g
B 58.5g
C 85.5g
D 88.5g

Question 18:

Soap lather is an example of a colloid in which a?

A Liquid is dispersed in gas
B Solid is dispersed in liquid
C Gas is dispersed in liquid
D Liquid is despersed in liquid

Question 19:

The pH of a solution obtained by mixing 100cm³ of a 0.2M solution of NaOH is?

A 1.3
B 7.0
C 9.7
D 12.7

Question 20:

Mg²⁺_(aq) + 2e^->_(aq) â†’ Mg_(s)E°_(volts) = 2.370
Zn²⁺_(aq) + 2e^->_(aq) â†’ Zn_(s)E°_(volts) = -0.763
Cds²⁺_(aq) + 2e^->_(aq) â†’ Cd_(s)E°_(volts) = 0.403
Cu²⁺_(aq) + 2e^->_(aq) â†’ Cu_(s)E°_(volts) = 0.340
In the electrochemical series above, the strongest reducing agents is?

A Cu _(s)
B Cd_(s)
C Znsub>(s)
D Mg_(s)