JAMB UTME - Chemistry - 1987

A stream of air was successively passed through three tubes X, Y and Z containing a concentrated aqueous solution of KOH, red hot copper powder and fused calcium chloride respectively. What was the composition of the gas emanating from tube Z?

Antwortdetails

The best treatment for a student who accidentally poured concentrated tetraoxosulphate (VI) acid on his skin in the laboratory is to wash the skin with?

Antwortdetails

If d represents the density of a gas and K is a constant, the rate of gaseous diffusion r is related to d by the equation?

Antwortdetails

r = k /√d

Ethanol reacts with aqueous sodium mono-oxoio date (l) to give a bright yellow solid with a characteristic smell. The product is?

Antwortdetails

The atomic numbers of two elements X and Y are 12 and 19 respectively. The bond of these two elements is?

Antwortdetails

When sodium hydroxide is heated with ammonium tetraoxosulphate (IV), the gas given off may be collected by?

Antwortdetails

The efficiency of petrol as a fuel in high-compression internal combustion engines improves with an increase in the amount of?

Antwortdetails

Oil spillage in ponds and creeks can be cleaned up by?

Antwortdetails

The most volatile fraction obtained from fractional distillation of crude petroleum contains?

Antwortdetails

Magnesium ribbon was allowed to burn inside a given gas P leaving a white solid residue Q. Addition of water to Q liberated a gas which produced dense white fumes with a drop of hydrochloric acid. The gas P was?

Antwortdetails

Alloys are best prepared by?

Antwortdetails

Which of the following water samples will have the highest titre value when titrated for the Ca2+ ions using soap solution?

Antwortdetails

An isotope has an atomic number of 17 and a mass number of 36. Which of the following gives the correct number of neutrons and protons in an atom of the isotope?

Antwortdetails

Mass number = number of protons + number of neutrons
36 = 17 + X; X = 36 -17 = 19
19 neutrons and 17 protons

The greater the different in electronegativity between bonded atoms, the?

Antwortdetails

Use the option above to answer this question. Which is the correct set of results for tests conducted respectively on fresh lime juice and ethanol.

Antwortdetails

In the purification of town water supply, alum is used principally to?

Antwortdetails

Stainless steel is an alloy of?

Antwortdetails

The solubility of Na3AsO4(H2O)12 is 38.9g per 100g H2O. What is the mass percentage of Na3AsO4 in the saturated solution?

(As = 75, Na = 23, O = 16, H = 1)

Antwortdetails

Which of the following elements will form oxide which will dissolve both in dilute HNO3 and NaOH solutions to form salts?

Antwortdetails

An element Z, contained 90% of 168Z and 10% of Z1818 its relative atomic mass is?

Antwortdetails

Mass number of Z = 16 while that of Z is 18
90 x 16 = 14.4 10 x 18 = 1.8
100 1 100 1
it relative atomic mass = 14.4 + 1.8 = 162

In which of the following pairs of element is allotropy exhibited by each element?

Antwortdetails

Local black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the?

Antwortdetails

Which of the following compounds will give a precipitate with an aqueous ammoniacal solution of copper (l) chloride?

Antwortdetails

HC = C-CH2CH3

Inspite of the electronic configuration, 1s22s22p2, carbon is tetraavalent because?

Antwortdetails

both the 2s and 2p orbitals hydrodizes

The reaction between sulphur (IV) oxide and oxygen is represented by the equilibrium reaction 2SO2(g) + O2(g) ↔ 2SO3(g), ∆H = -196 kJ. What factor would influence increased production of SO3(g)?

Antwortdetails

In which of the following are the aqueous solutions of each of the substances correctly arranged in order to decreasing acidity?

Antwortdetails

Corrosion is exhibited by

Antwortdetails

When water drops are added to calcium carbide in a container and the gas is passed through a jet and lifted, the resultant flame is called an?

Antwortdetails

Which of the following gases can best be used for demonstrating the fountain experiment?

I) Nitrogen (ii) Ammonia (iii) Nitrogen (I) oxide

(iv) Hydrogen chloride.

Antwortdetails

If 24.83 cm3 of 0.15 M NaOH is titrated to its end point with 39.45 cm3 of HCl, what is the molarity of the HCl?

Antwortdetails

NaOH + HCl → NaCl + H2O moles ratio = 1/1
↔ (MaVa) / Mb x 39.45 = 0.094

Complete oxidation of propan -1- ol gives?

Antwortdetails

Synthetic rubber is made by polymerization of?

Antwortdetails

The times taken for iodine to be liberated in the reaction between sodium thiosulphate and hydrochloric acid at various temperature are as follows. These results suggest that

Antwortdetails

Use the option above to answer this question. The structure of benzoic acid is

Antwortdetails