2018 - JAMB Chemistry Past Questions and Answers - page 2
3H\(_{2(g)}\)+ N2 ⇔ 2NH\(_{3(g)}\) ; H= -ve
In the reaction above, lowering of temperature will
N\(_{2(g)}\) + 3H\(_{2(g)}\) ⇔ 2NH\(_{3(g)}\) In the Haber process, the forward reaction is exothermic and the backward reaction is endothermic. If the temperature is decreased, the yield from the exothermic direction is increased i.e. the forward reaction is increased.
Users' Answers & CommentsThe situation obtained when a perfect gas expands into a vacuum is
Formula for enthalpy change: ΔH = ΔU + Pex(ΔV)
The enthalpy change is zero because both terms on the right are zero in free expansion of an ideal gas.
There is no external pressure in a free expansion, so P (ex) = 0. And the internal energy change, ΔU of free expansion in a closed system is zero since no inter molecular forces have to be overcome. The temperature remains constant and no heat is absorbed or released.
Users' Answers & CommentsThe general formula of alkanones is
Alkanones (also known as ketones) have the general formula R\(_2\)CO
Users' Answers & CommentsThe alkanoic acid found in human sweat is
Sweat consists primarily of water and electrolytes. The primary electrolytes contained in sweat are sodium and chloride. Potassium, urea, lactate, amino acids, bicarbonate and calcium are also found.
Users' Answers & CommentsThe elements in the periodic table are listed in order of increasing
The periodic number table is arranged in order of atoms increasing atomic number
Users' Answers & CommentsH\(_2\) S\(_{(g)}\) + Cl\(_{2(g)}\) → 2HCl\(_{(g)}\) + S\(_{(g)}\) In the reaction above, the substance that is reduced is
Which of the compounds is composed of Al, Si, O and H?
Image result for chemical composition of claywww.researchgate.net Between the five main minerals found in clay, kaolinite is the most common. Kaolinite holds the chemical composition Al2Si2O5(OH)4 and is an aluminum silicate material with a low “shrink-swell” capacity. It is a soft, white mineral but is often colored orange or red by iron oxide found in the soil
Clay minerals are hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces.
Users' Answers & CommentsWhen large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as
In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. Wikipedia
Users' Answers & CommentsA given amount of gas occupies 10.0dm5 at 4atm and 273°C. The number of moles of the gas present is [Molar volume of gas at s.t.p = 22.4dm\(^3\)]
According to Charles' law, the volume of a gas becomes zero at