JAMB UTME - Chemistry - 1983

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

The molecular formula of X is

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

Reaction of X with yeast forms the basis of the

zn + 2HCl → ZnCl2 + H2The rate of the above reaction will be greatly increased if

The colour imparted to a flame by calcuium ion is

Which of the following solutions will give a white precipitate with barium chloride solution and a green flame test?

Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine?

A mixture of common salt, ammonium chloride and barium sulphate can best be separated by

Which of the following happens during the electrolysis of molten sodium chloride?

The alkanol obtained from the production of soap is

In the reaction Fe + Cu2+ $\to$ Fe2+ + Cu,iron displaces copper ions to from copper. This is due to the fact that

A gas that can behave as a reducing agent towards chlorine and as an oxidizing agent toward hydrogen sulphide is

When sodium dioxonitrate (lll) (NaNO2) dissolves in water, ∆H is positive. The process of dissolution is

Which volume of 0.5 M H 2SO4 will exactly neutralize 20 cm 3 of 0.1 M NaOH solution?

Answer Details

$\frac{C_A{V}_A}{C_b{V}_b}=\frac{1}{2}$

$frac0.5\times V_{A}0.1\times 20=\frac{1}{2}$

\(V_A = \frac{0.1 \times 20}{2 \times 0.5} = \frac{1.0}{0.5)\)

= 2cm2

Some metals are extracted from their ores after some preliminary treatments by electrolysis (L), some of both processes (TL). Which set-up in the following for the extraction of ion, copper and aluminium is correct?

The cracking process is very important in the petroleum industry because it.

Some copper (ll) sulphate pentahydrate (CuSO4 5H2O), was heated at 120 oC with the following results. Wt of crucible = 10.00 g; Wt of crucible + CuSO4 5H2O =14.98g; Wt of crucible + residue = 13.54 g. How many molecules of water of crystalization were lost?

[H = 1, Cu = 63.5, O = 16, S = 32]

Answer Details

CuSO4 + 5H 2O
Wt CuSO4 + 5H2O = 14.98 - 10.00
= 4.98 gm
Wt of residue or CuSO4 = 13.54 - 10.00 =3.54
Wt of water lost = 4.98 - 3.54 = 1.44
Molecules of H2O lost = 5 - 1 = 4

In the above experiment, the litmus paper will initially

Sodium sulphate decahydrate (Na2SO4.10 H2O) on exposure to air loses all its water of crystallization.

The process of loss is known as

In the reaction M + N P;∆H = + QKJ. Which of the following would increase the concentration of the product?

The flame used by welders in cutting metals is

The three-dimensional shape of methane is

A piece of burning sulphur will continue to burn in a gas jar of oxygen to give misty fumes which readily dissolved in water. The resulting liquid is

Zn + H2 SO4 → ZnSO4 + H2

In the above reaction how much Zinc will be left of 1.0 M of H2SO?

[Zn =65, s = 32, O = 16, H = 1]

How many isomeric forms are there for the molecular formula C3H6Br2?

In the experiment above, a current was passed for 10 minutes and 0.63g of copper was found to be deposited on the cathode of CuSO4 cells. The weight of silver deposited on the cathode og AgNO3 cell during the same period would be? [Cu = 63, Ag = 108]

Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct?

Stainless steel is an alloy of

Increasing the pressure of a gas

Which of the following relationships between the pressure P, the volume V and the temperature T, represents an ideal gas behaviour?

A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is

30 cm3 of 0.1 M Al (NO3)3 SOLUTION IS RECTED WITH 100cm3 of 0.15M of NaOH solution. Which reactant is in excess, and by now much ?

Which of the following statements is FALSE?

3. 06 g of a sample of potassium trioxochlorate (V) (KCIO) was required to make a saturated solution with 10cm3 of water at 25oC. The solubility of the salt at 25oC is [K =39, Cl = 35.5, O = 16]

Which of the following pair of gases will NOT react further with oxygen at a temperature between 30oC AND 400oC

C2H5 - C = CH2

CH3The correct name of the compound with the above structural formula is

In the reactions

(I) H2 (g) + 1/2O2(g) → H2O(l); ∆H = -286 KJ

(II) C(s) + O2g) → CO2 (g); ∆H = -406 KJ the equations imply that

Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed or removed by

The mass of an atom is determined by

Which of these metals, Mg, Fe, Pb and Cu will dissolve in dilute HCI?

X is a crystalline salt of sodium solution of X in water turns litmus red and produces a gas which turns lime water milky when added to sodium carbonate. With barium chloride solution, X gives hydrochloric acid. X is

An element is electronegative if

2.5 g of a hydrate barium salt gave on heating, 2.13 g of the anhydrous salt. Given that the relative molecular mass of the of the anhydrous salt is 208, the number of molecules of water of crystallization of the barium salt is

In the preparation of some pure crystals of Cu (NO3)2 starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ?

Consecutive members of an alkane homologous serires differ by

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

Which of the following is a neutralization reaction?

Liquid X, reacts with sodium trioxocarbonate (IV) (Na2CO3) to give a gas which turns calcium chloride solution milky X is

The equilibrium reaction between copper (l) chloride and chlorine at 25oC and 1 atmosphere is represented by the equation:

2CuCl +Cl2 ⇌ 2 CuCl2 ∆H = - 166 KJ. Which of the following statements is TRUE for the reaction, pressure remaining constant?

If an element has the electronic configuration 1s 2 2s2 2p3 3s2 3p4, it is

In which of the following processes is iron being oxidized?1 Fe + H2SO4 → FeSO4 +H22 FeSO4 + H2S → FeS + H2SO43 2FeCI2 + Cl2 → 2FeCl34 2FeCl3 + SnCl2 + → 2FeCl2 + SnCl4