Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?

Filtration followed by distillation

Neutralization with sodium hydroxide followed by distillation

Neutralization with sodium hydroxide followed by filtration

2KClO3(g) MNO3? 2KCl(s) + 3O2(g) The importance of the catalyst in the reaction above is that

the reaction takes place more rapidly at a lower temperature

heating may not be required before the reaction takes place

the reaction is controllable even at a high temperature

the reaction produces large quantity of oxygen

the reaction takes place more rapidly at a lower temperature

Beryllium and Aluminium have similar properties because they

are positioned diagonally to each other

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

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

In the laboratory preparation of oxygen, the gas cannot be collected by displacement of air because

the density of oxygen is greater than that of air

the density of air is nearly the same as that of oxygen

JAMB UTME - Chemistry - 2018 | Green Bridge CBT

Question 1 Report

The number of electrons in the valence shell of an element of atomic number 14 is?

1

2

3

4

Answer Details

The number of electrons in the valence shell of an element can be determined by using the periodic table and the electron configuration of the element. The valence shell is the outermost shell that contains electrons that are involved in chemical reactions. For an element with atomic number 14, which is silicon, the electron configuration is 1s2 2s2 2p6 3s2 3p2. The valence shell of silicon is the third shell, which contains 3s2 and 3p2 electrons. Therefore, the number of electrons in the valence shell of silicon is 4 electrons.






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