Daily NEET MCQ- April 4, 2022 - NEET MCQ

Coefficient of performance of a refrigerator is defined as the ratio of heat extracted from the cold reservoir to the work done on the refrigerator. It is denoted by α = Q₂/W.

In a refrigerator, the working substance(gas) first gets expanded from high to low pressure which cools it into a vapour-liquid mixture. Then heat is absorbed from the region to be cooled. Then the external work done on the system heats up the vapour. Finally, the vapour’s heat is released to the surroundings.

A bomb calorimeter operates at a constant volume i.e. it is an isochoric process. So the heat capacity is C_V which represents heat capacity at constant volume. While C_P represents heat capacity at constant pressure.

A bomb calorimeter is used to measure the heat of combustion of a reaction. It has to withstand a large amount of pressure, in order to determine the heat of combustion. It is an isochoric process and the heat energy is equal to the internal energy.

ATP is utilised as and when needed. Substrates enter the pathway and are withdrawn from it as and when necessary. Enzymatic rates in these pathways are controlled by multiple means.

Aerobic respiration involves the complete oxidation of glucose. There can be a net gain of 38 ATP molecules during aerobic respiration of one molecule of glucose.

In fermentation, there is a net gain of only two molecules of ATP for each molecule of glucose degraded to pyruvic acid whereas many more molecules of ATP are generated under aerobic conditions.

RQ stands for Respiratory Quotient. It is the ratio of the volume of CO₂ evolved to the volume of O₂ consumed in respiration. It is also known as the respiratory ratio.

Fuel obtained from plastic waste has high octane rating. It contains no lead and, therefore, is known as green fuel. Due to recent developments made in chemical and textile industries, clothes will be made from recycled plastic waste. These will be available soon in the global textile market.

Heat required to eliminate water : n x Δ_vapH^– = (1 mol) × (44.01 kJ mol^–1) = 44.01 kJ mol^-1. Δ_vapor = Δ_vapH – ΔnRT = 44.01 kJ mol^-1 – 1×8.314 J/K-mol x 298 k x 10^-3 = 41.53 KJ/mol. So the amount of energy needed is 41.53 KJ/mol.