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Chemistry
UTME / JAMB 1983
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine?
A
Fractional distillation without a dehydrant
B
simple distillation with a dehydrant
C
fractional distillation with a dehydrant
D
column chromatography
E
evaporation
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Fractional distillation with a dehydrant is the most likely separation process to yield high-quality ethanol from palm wine. Adding a dehydrant helps to remove water from the ethanol more effectively during the distillation process, resulting in a higher purity of ethanol. This is important for producing high-quality ethanol suitable for various applications, including consumption or industrial use.
Source: Myschool Past Questions Archive (Record #30845)
Chemistry
UTME / JAMB 1983
Stoichiometry, Mole Concept & Volumetric Analysis
Increasing the pressure of a gas
A
lowers the average kinetic energy of the molecules
B
decreases the density of the gas
C
decreases the temperature of the gas
D
increases the density of the gas
E
increases the volume of the gas
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #30846)
Chemistry
UTME / JAMB 1983
Nature of Matter & Separation Techniques
Solution
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
A
10
B
7
C
5
D
2
E
1
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Given:
Mass of hydrated Barium salt = 2.5g
Mass of anhydrous Barium salt = 2.13g
Molar mass of anhydrous salt = 208
Molar mass of anhydrous salt = 208 + 18x ( 18x due to the unknown molecule of water of crystallization, i.e xH2O, since Molar mass of H2O = 18, then multiplied by X)
To calculate the number of water of crystallization, we use the formula:
\(\frac{mass of hydrated salt}{mass of anhydrous salt}\) = \(\frac{Molar mass of hydrated salt}{Molar mass of anhydrous salt}\)
\(\frac{2.5}{2.13}\) = \(\frac{208 + 18x}{208}\)
2.13 (208 + 18x) = 2.5 x 208
443.04 + 38.34x = 520
38.34x = 520 - 443.04
38.34x = 76.96
x = \(\frac{76.96}{38.34}\)
x = 2.00
Therefore, the number of water of crystallization is 2
Source: Myschool Past Questions Archive (Record #30847)
Chemistry
UTME / JAMB 1983
Water, Solutions & Solubility
Solution
3. 06 g of a sample of potassium trioxochlorate (V) (KCIO\(_3\)) was required to make a saturated solution with 10cm\(^3\) of water at 25^\circC. The solubility of the salt at 25^\circC is [K =39, Cl = 35.5, O = 16]
A
5.0 moles dm3
B
3.0 moles dm3
C
2.5 moles dm3
D
1.0 molesv
E
0.5 moles dm3
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Molar mass of KCIO\(_3\) = 122.5 g/mol
3.06g = 10
xg = 1000
\(frac{3.06 * 1000}{10}\)
= 306g
Molar conc = \(frac{Mass conc}{Molar mass}\)
Molar conc = \(frac{306}{122.5}\)
= 2.497mol/dm\(^3\)
Source: Myschool Past Questions Archive (Record #30848)
Chemistry
UTME / JAMB 1983
Organic Chemistry I: Hydrocarbons & Crude Oil
The cracking process is very important in the petroleum industry because it.
A
gives purer products
B
yields more lubricants
C
yields more engine fuels
D
yields more asphalt
E
yields more candle wax
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #30849)
Chemistry
UTME / JAMB 1983
Oxidation, Reduction & Redox Reactions
A gas that can behave as a reducing agent towards chlorine and as an oxidizing agent toward hydrogen sulphide is
A
O2
B
NO
C
SO2
D
NH3
E
CO2
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #30853)
Chemistry
UTME / JAMB 1983
Metals, Transition Elements & Extraction
Which of the following solutions will give a white precipitate with barium chloride solution and a green flame test?
A
Na2SO4
B
CuSO4
C
CaSO4
D
CaCI2
E
(NH4)2SO4
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #30855)
Chemistry
UTME / JAMB 1983
Atomic Structure, Orbitals & Nuclear Chemistry
The mass of an atom is determined by
A
its ionization potential
B
its electrochemical potential
C
the number of protons and electrons
D
the number of neutrons and protons
E
the number of neutrons and electrons
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #30858)
Chemistry
UTME / JAMB 1983
Acids, Bases, pH & Salts
Which of the following is a neutralization reaction?
A
Addition of sodium chloride solution to potassium chloride solution
B
Addition of trioxonitrate (V) acid (nitric acid) to distilled water
C
Addition of trioxonitrate (V) acid (nitric acid) to tetraoxosulphate (IV) acid (sulphuric acid)
D
Addition of trioxonitrate (V) acid (nitric acid) to potassium trioxonitrate (V) (potassium nitrate) solution
E
Addition of trioxonitrate (V) acid (nitric acid) to potassium hydroxide solution
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #30861)
Chemistry
UTME / JAMB 1983
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
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
A
1,800 kg
B
900 kg
C
600 kg
D
2, 400 kg
E
1, 200 kg
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
2\(C_2H_6 + 7O_2 →4CO_2 + 6H_2O\)
addition of oxygen causes weight gain, expelled \(CO_2\) results in weight loss
for oxygen added;
2moles \(C_2H_6\) = 7moles \(O_2\)
2(30)g \(C_2H_6\) = 7(2)(16)g \(O_2\)
3000kg \(C_2H_6\) = X kg \(O_2\)
cross multiplying X = 11200kg
for \(CO_2\) expelled;
2moles \(C_2H_6\) = 4moles \(CO_2\)
2(30)g \(C_2H_6\) = 4(44)g \(CO_2\)
3000kg \(C_2H_6\) = Y kg \(CO_2\)
cross multiplying Y = 8800kg
since X > Y, the plane has a net weight gain.
Net weight gain = X - Y = 11200-8800 = 2400kg.
Source: Myschool Past Questions Archive (Record #30874)
Chemistry
UTME / JAMB 1983
Stoichiometry, Mole Concept & Volumetric Analysis
Liquid X, reacts with sodium trioxocarbonate (IV) (Na2CO3) to give a gas which turns calcium chloride solution milky X is
A
Na2SO4(aq)
B
Kl (aq)
C
an alkali
D
an acid
E
a hydrocarbon
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #30879)
Chemistry
UTME / JAMB 1983
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following statements is FALSE?
A
Copper (ll) ion can be reduced to copper (l) ion by hydrochloric acid and zinc
B
Sodium metal dissolves in water giving oxygen
C
Nitrogen is insoluble in water
D
Carbondioxide is soluble in water
E
lead has a higher atomic weight than copper
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #30880)
Chemistry
UTME / JAMB 1983
Chemical Energetics & Thermochemistry
When sodium dioxonitrate (lll) (NaNO2) dissolves in water, ∆H is positive. The process of dissolution is
A
exothermic
B
endothermic
C
isothermal
D
isomeric
E
hygroscopic
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #30888)
Chemistry
UTME / JAMB 1983
Reaction Rates & Chemical Equilibrium
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?
A
more CuCl is formed at 40oC
B
more CuCl2 is formed at 10oC
C
Less CuCl2 is formed at 10oC
D
there is no change in the amount of CuCl2 formed at 40oC and10oC
E
more CuCl is consumed at 40oC
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #30891)
Chemistry
UTME / JAMB 1983
Stoichiometry, Mole Concept & Volumetric Analysis
zn + 2HCl → ZnCl2 + H2
The rate of the above reaction will be greatly increased if
A
the zinc is in the powered form
B
a greater volume of the acid is used
C
a smaller volume of the acid is used
D
the reaction vessel is immersed in an ice-bath
E
the zinc is in the form of pellets
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #30896)