10 questions. Try each one, then open the answer to check yourself and read the explanation.
Which of the following oxides is both acidic and basic in nature?
Answer: C (Al2O3)
Aluminium oxide is amphoteric: it reacts with both acids and alkalis. CO2 and P4O10 are acidic, Na2O is basic.
A sample of gas occupies 200cm3 at 27°C. What volume will it occupy at 127°C, if the pressure is constant?
Answer: A (267cm3)
Charles' law with kelvin temperatures: V2 = 200 × 400 ÷ 300 = 266.7 ≈ 267 cm3.
The deviation of real gases from ideal behavior is mainly due to
Answer: D (intermolecular forces and finite molecular volume)
An ideal gas is imagined to have no attractions between particles and particles of no size. Real gas particles attract each other and have their own volume, which is why they deviate, especially at high pressure and low temperature.
If the enthalpy of combustion of ethanol is −1370KJmol−1, what is the enthalpy change for the combustion of 100g of ethanol? (C = 12, H = 1, O = 16)
Answer: D (−2978kJ)
Molar mass of C2H5OH = 46 g/mol, so 100 g is 100/46 = 2.174 mol. ΔH = 2.174 × (−1370) ≈ −2978 kJ.
A catalyst increases the rate of a reaction by
Answer: C (lowering the activation energy)
A catalyst gives the reaction an alternative route with a lower activation energy; it does not change the equilibrium or the enthalpy change.
The pH of a solution increases from 4 to 6. The hydrogen ion concentration becomes
Answer: D (one-hundredth its initial value)
[H+] goes from 10−4 to 10−6 mol/dm3, a 100-fold decrease, so it becomes one-hundredth of the original.
Which of the following salts will hydrolyze in water to produce a basic solution?
Answer: D (CH3COONa)
Sodium ethanoate comes from a weak acid and a strong base, so its ethanoate ions react with water to give OH− ions. NH4Cl gives an acidic solution; NaCl and KNO3 are neutral.
The IUPAC name of CH3CH2CH(OH)CH3 is:
Answer: B (Butan-2-ol)
The chain has four carbons (butane) and the OH is on carbon 2 when numbered from the nearer end, so it is butan-2-ol.
Which class of organic compounds is formed when a carboxylic acid reacts with an alcohol?
Answer: C (Ester)
Acid + alcohol gives an ester and water (esterification).
In the contact process for the manufacture of H2SO4, the catalyst used is:
Answer: B (Vanadium (v) oxide)
Vanadium(V) oxide, V2O5, catalyses the oxidation of SO2 to SO3 in the contact process.