2017 - JAMB Chemistry Past Questions and Answers - page 2

Expression for equilibrium constant

k = (\frac{\text{concentration of product}}{\text{concentration of reactant}})

At constant pressure connotes Charle's law

(\frac{V_1}{T_1}) = (\frac{V_2}{T_2})

(\frac{2dm^3}{300k}) = 2 x (\frac{2dm^3}{T_2})

T₂= 600k

C₅H₁₂ has 5 carbons acid 12 hydrogens.

2–methyl butane

No of carbon=5

No of hydrogen=12

Xanthopreitic test for the presence of protein, when conc nitric acid is added to the drop, an intense yellow colouration is observed.

It contains all the functional group of protein which includes the amino, alkanol and the carboxylic group. Adding few drops of conc HNO₃ to a protein, gives an intense yellow colouration.

It is called Xanthopreitic test.

P^H = - Log[ H⁺ ]

P^H + P^OH =14

P^OH = 14 - 3.8

P^OH = 10.2

P^OH = - Log[ OH^- ]

10.2 = - Log[ OH^- ]

10^-10.2 = [ OH^- ]

[ OH^- ] = 6.3 x 10^-11

C₂H₅OH → CH₃CHO → CH₃COOH

Ethanol.....oxidation Ethanal........Ethanoic Acid

Primary alcohol oxidises to aldehyde and later to carboxylic acid.

Secondary alcohol oxidises to ketones.

Ethanol is an example of primary alcohol and primary alcohol can be oxidised to aldehyde and carboxylic acid. Wherein, incomplete oxidation of primary alcohol yields aldehyde also known as alkaline while complete oxidation of primary alcohol yields carboxylic acid.

This is a solution formed from the hydrolyses of an alkali in water.

At high temperature and low pressure, the vanderwaal equation is reduced to ideal gas equation.

i.e, [P + (\frac{a}{v^2})] [v - b] = RT is reduced to PV = nRT

Generally, a gas behaves more like an ideal gas at higher temperature and lower pressure as the potential energy due to intermolecular forces, it becomes less significant compared with the particles kinetic energy and the size of the molecules, then it becomes less significant compared to the empty space between them.

When ΔH is negative, heat is liberated to the surrounding and it connotes an exothermic reaction.

ΔH = −ve