Which of the following is a characteristic of a gas?
Gases are highly compressible due to large spaces between particles.
Which of the following is an example of a mixture?
Blood is a mixture of cells, plasma, and other components.
Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V) [Ca = 40, N = 14, O = 16]
Molar mass of Ca(NO₃)₂ = 164; %N = (2×14)/164 × 100 = 17.1%.
The droplets of water observed around a bottle of milk taken out of the refrigerator is due to the fact that the
Water vapour condenses as it loses energy to the cold bottle.
The volume of a given gas is V cm³ at P mm Hg, what is the new volume of the gas if the pressure is reduced to half at constant temperature?
Boyle’s law: P₁V₁ = P₂V₂; V₂ = V × (P/P/2) = 2V cm³.
Moving from left to right across a period, the general rise in the first ionization energy can be attributed to the
Nuclear charge increases, making electrons harder to remove.
How many unpaired electron(s) are there in the nitrogen sub-levels?
Nitrogen (1s² 2s² 2p³) has 3 unpaired electrons in 2p.
The stability of the noble gases is due to the fact that they
Noble gases have stable octet/duplet electron configurations.
The maximum number of electrons in the L shell of an atom is
L shell (n=2) can hold 2n² = 2×2² = 8 electrons.
Elements in the same period in the periodic table have the same
Same period means same number of electron shells.
²₁D + ³₁T → ⁴₂He + ¹₀n + energy. The reaction above illustrates
Deuterium and tritium combine to form helium: nuclear fusion.
A noble gas with a high power of fog penetration used in aerodrome beacons is
Krypton’s light penetrates fog, used in aerodrome beacons.
Permanent hardness of water can be removed by
Caustic soda removes permanent hardness by precipitation.
Substance employed as drying agents are usually
Hygroscopic substances absorb moisture, used as drying agents.
Calculate the solubility in mol dm⁻³ of 40g of CuSO₄ dissolved in 100g of water at 120°C. [Cu = 64, S = 32, O = 16]
Molar mass CuSO₄ = 160; moles = 40/160 = 0.25; solubility = 0.25/0.1 = 2.5 mol dm⁻³.
Coffee stains can best be removed by
Ammonia solution effectively removes organic coffee stains.
Carbon (IV) oxide is mainly dangerous if inhaled because it
CO₂ reduces oxygen availability in blood, causing suffocation.
The acid that is used to remove rust is
Hydrochloric acid dissolves rust (iron oxide) effectively.
Calculate the volume of 0.5 mol dm⁻³ H₂SO₄ that is neutralized by 25 cm³ of 0.1 mol dm⁻³ NaOH
Moles NaOH = 0.1 × 0.025 = 0.0025; H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O; moles H₂SO₄ = 0.00125; volume = 0.00125/0.5 = 0.0025 dm³ = 2.5 cm³.
The colour of methyl orange in alkaline medium is
Methyl orange turns yellow in alkaline medium (pH > 4.4).
Which of the following salts is slightly soluble in water?
CaSO₄ is slightly soluble; others are either very soluble or insoluble.
6AgNO₃(aq) + PH₃(g) + 3H₂O(l) → 6Ag(s) + H₃PO₃(g) + 6HNO₃(aq). In the above reaction, the reducing agent is
PH₃ is oxidized to H₃PO₃, making it the reducing agent.
The IUPAC nomenclature of the compound LiAlH₄ is
LiAlH₄ is named lithium tetrahydridoaluminate (III) in IUPAC.
Iron can be protected from corrosion by coating the surface with
Zinc (galvanizing) protects iron by sacrificial corrosion.
What quantity of aluminium is deposited when a current of 10A is passed through a solution of an aluminium salt for 1930s? [Al = 27, F = 96500 C mol⁻¹]
Q = It = 10×1930 = 19300 C; Al³⁺ + 3e⁻ → Al; moles Al = 19300/(3×96500) = 0.0667; mass = 0.0667×27 = 1.8 g.
In the preparation of oxygen by heating KClO₃ in the presence of MnO₂, only moderate heat is needed because the catalyst acts by
MnO₂ lowers the activation energy, speeding up the reaction.
The rate of a chemical reaction increases when the particle size of a solid reactant is reduced. This is due to
Smaller particle size increases surface area, allowing more collisions and a faster reaction rate.
2H₂(g) + O₂(g) ⇌ 2H₂O(g) ∆H = -ve. What happens to the equilibrium constant of the reaction above if the temperature is increased?
Exothermic reaction: increasing T shifts equilibrium left, K decreases.
When copper reacts with concentrated nitric acid, the gas produced is
Copper reacts with concentrated HNO₃ to produce NO₂ gas: Cu + 4HNO₃ → Cu(NO₃)₂ + 2NO₂ + 2H₂O.
To a solution of an unknown compound, a little dilute tetraoxosulphate (VI) acid was added with some freshly prepared iron (II) tetraoxosulphate (VI) solution. The brown ring observed after the addition of a stream of concentrated tetraoxosulphate (VI) acid confirmed the presence of
Brown ring test confirms the presence of nitrate ions (NO₃⁻).
Which of the following is used in rocket fuels?
HNO₃ is used as an oxidizer in rocket fuels.
In the preparation of dry chlorine gas, the drying agent used is
Concentrated sulfuric acid is used to dry chlorine gas due to its hygroscopic nature.
A compound gives an orange-red colour to non-luminous flame. This compound is likely to contain
Calcium (Ca²⁺) gives an orange-red flame in flame tests.
Stainless steel is used for making
Stainless steel’s durability makes it ideal for tools.
The residual solids from the fractional distillation of petroleum are used as
Residual solids (bitumen) are used for coating pipes.
The functional group in ethanol is
Ethanol (C₂H₅OH) contains the hydroxyl (-OH) functional group.
Which element in period 3 forms a covalent compound with chlorine?
Phosphorus (non-metal) forms covalent PCl₃ or PCl₅ with chlorine.
In the electrolysis of brine, the gas produced at the anode is
Chlorine gas is produced at the anode during the electrolysis of brine.
The type of bond in nitrogen gas (N₂) is
Nitrogen gas has a triple covalent bond between two nitrogen atoms.
The major source of air pollution in urban areas is
Vehicle emissions release significant pollutants like CO and NOₓ in urban areas.
Now practice in exam mode
You've studied the answers — now test yourself under real exam conditions with the timer running.
Start JAMB Chemistry 2001 Quiz