UNN Chemistry 2014/2015 Day 2 Past Questions

Practice each question, then open it to see the full details.

A mixture of sand, ammonium chloride and sodium chloride is best separated by

A.sublimation followed by addition of water and filtration
B.sublimation followed by addition of water and evaporation
C.addition of water followed by filtration and sublimation
D.addition of water followed by crystallization

Which of the following elements is common to bronze and soft solder?

A.tin
B.lead
C.copper
D.zinc

A solution of calcium bromide contains 20g/dm³. What is the molar concentration of calcium bromide relative to bromide ions?
[Ca = 40, Br = 80]

A.0.1, 0.1
B.0.1, 0.2
C.0.1, 0.05
D.0.05, 0.1

Haze is an example of

A.colloid
B.suspension
C.emulsion
D.aerosol

The volume of 0.20moldm^-3 H₂ H₂SO₄ that will exactly neutralize 25cm³ of 0.05moldm^-3 KOH solution is

A.3.1 cm³
B.15.6 cm³
C.10.4 cm³
D.26.2 cm³

If the relative rate of diffusion of a gas is 0.25 and that of Cl₂ under the same condition is 0.20, calculate the relative molecular mass of the gas.

A.22.7
B.45.4
C.68.1
D.90.8

The oxidation states of Chlorine in HOCl, HClO₃, and HClO₄, respectively are

A.-1, +5, and +7
B.-1, -5, and +7
C.+1, +3 and +4
D.+1, +5 and +7

What is the sign of ∆H and ∆S in the following reaction?
C_(s) + O_2(g) --> CO_2(g)
∆H ∆S

A.+ 0
B.- +
C.+ -
D.- 0

In the periodic table, what is the property that decreases along the period and increases down the group?

A.atomic number
B.electron affinity
C.ionization potential
D.atomic radius

Rusting of iron is

A.Redox reaction
B.Decomposition reaction
C.Catalytic reaction
D.Reversible reaction