A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

adding excess calcium hydroxide

adding a calculated amount of calcium hydroxide

The presence of ammonia gas in a desiccator can exclusively be removed by

concentrated tetraoxosulphate (VI) acid

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

collisions are perfectly elastic

forces of repulsion and attraction are in equilibrium

In the upper atmosphere, the ultra-violet light breaks off a free chlorine atom from chlorofluorocarbon molecule. The effect of this is that the free chlorine atom will

be very reactive and will attack ozone

be non-reactive and will not attack ozone

not change the level of ozone in the atmosphere

increase the level of ozone in the atmosphere

(I). 3CuO(s) + 2NH3(g) -----> 3Cu(s) + 3H2O(l) + N2(g) (II). 2NH3(g) + 3Cl2(g) -----> 6HCl(g) + N2(g) (III). 4NH3(g) + 3O2(g) -----> 6H2O(l) + N2(g) The reactions represented by the equations above demonstrate the

oxidizing properties of ammonia

The ionic radii of metals are usually

greater than their atomic radii

unaffected by the charge on the ion

Suitable reagents for the laboratory preparation nitrogen are

sodium dioxonitrate(III) and ammonium chloride

sodium trioxonitrate(V) and ammonium chloride

sodium chloride and ammonium trioxonitrate(V)

sodium chloride and ammonium di-ozonitrate(III)

The collision theory explains reaction rates in terms of

frequency of collision of the reactants

frequency of collision of the products

The conductivity of an acid solution depends on the

amount of ions present and their mobilities

Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

Q will form an electrovalent bond with S

P will form an electrovalent bond with R

Q will form a covalent bond with S

R will form an electrovalent bond with S

Q will form an electrovalent bond with S

The situation obtained when a perfect gas expands into a vacuum is

ΔH is zero and T Δ S is positive

ΔH is positive and TΔ S is zero

ΔH is positive and T Δ S is negative

ΔH is negative and TΔ S is zero

ΔH is zero and T Δ S is positive

JAMB UTME - Chemistry - 2018 | Green Bridge CBT

Question 1 Report

If one of the following oxides is heated with hydrogen or carbon using a bunsen burner. it is not reduced to the metal, Which one is it?

lead oxide

Magnesium oxide

Copper oxide

Tin oxide

Answer Details

The oxide that cannot be reduced to the metal when heated with hydrogen or carbon using a Bunsen burner is magnesium oxide. Magnesium oxide is an ionic compound made up of positively charged magnesium ions and negatively charged oxygen ions. When heated with hydrogen or carbon, the oxygen ions are not easily removed from the compound. This is because the ionic bond between the magnesium and oxygen ions is very strong and requires a lot of energy to break. On the other hand, lead oxide, copper oxide, and tin oxide are all metal oxides and can be reduced to the metal by heating with hydrogen or carbon. This is because they have a weaker bond between the metal and oxygen ions, allowing the oxygen to be removed more easily when heated. In conclusion, magnesium oxide is the oxide that cannot be reduced to the metal when heated with hydrogen or carbon using a Bunsen burner.






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