NEET Chemistry Questions: Chemical Thermodynamics

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The temperature of the system decreases in an




In an adiabatic process, there is no heat exchange with the surroundings. During adiabatic expansion, the system does work on the surroundings, and since no heat is added to the system, its internal energy decreases, resulting in a decrease in temperature.
If a refrigerator’s door is opened, then we get




When a refrigerator door is opened, the cooling system works harder to cool the extra warm air entering from the room. The heat extracted from the refrigerator's interior is released into the room, resulting in an overall increase in the room's temperature.
The cooling in refrigerator is due to




The cooling effect in a refrigerator is primarily due to the expansion of the refrigerant gas. When the gas expands, it absorbs heat from the refrigerator's interior, thereby cooling it.
The process, in which no heat enters or leaves the system, is termed as




An adiabatic process is a process in which no heat is transferred to or from the system. This means that during such a process, the total heat content of the system remains constant. This is in contrast to other types of processes like isochoric (constant volume), isobaric (constant pressure), and isothermal (constant temperature), where heat exchange can occur.
Warming ammonium chloride with sodium hydroxide in a test tube is an example of :




Warming ammonium chloride with sodium hydroxide in a test tube is an example of an open system. In an open system, both matter and energy can be exchanged with the surroundings. In this case, gases like ammonia may escape from the test tube, indicating the exchange of matter with the surroundings.
Out of boiling point (I), entropy (II), pH (III) and e.m.f. of a cell (IV), intensive properties are –




Intensive properties are those properties that do not depend on the amount of substance present. Out of the given options, boiling point (I), pH (III), and e.m.f. of a cell (IV) are intensive properties. Entropy (II), on the other hand, is an extensive property, as it depends on the amount of substance in the system.
A thermodynamic state function is




A thermodynamic state function is a quantity whose value depends only on the state of the system, not on how the system got to that state. Examples include internal energy, enthalpy, and entropy. This means that the value of a state function is determined solely by the current state of the system, irrespective of the path taken to reach that state.
In thermodynamics, a process is called reversible when




In thermodynamics, a process is called reversible when the surroundings are always in equilibrium with the system. This implies that the process can be reversed without leaving any change in either the system or the surroundings. In other words, the system and surroundings can be returned to their initial states with no net change.
Which one of the following statement is false–




Work is not a state function. Work depends on the path taken to reach one state from another, not just the initial and final states. Therefore, it is path-dependent. On the other hand, state functions like temperature, pressure, and volume depend only on the state of the system and not on how that state was achieved.
A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If OH is the enthalpy change and OE is the change in internal energy, then




In an exothermic reaction like the combustion of carbon monoxide to carbon dioxide, the enthalpy change (ΔH) is typically greater than the change in internal energy (ΔE). This is because ΔH accounts for the heat released to the surroundings at constant pressure, which includes the work done by the system due to volume change. The relationship can be expressed as ΔH = ΔE + PΔV, where PΔV is the work done by the system. Since gases are involved, PΔV is positive, making ΔH greater than ΔE.
At constant T and P, which one of the following statements is correct for the reaction, $ CO_{(g)} + { 1 \over 2 } O_{2(g) } \rightarrow CO_{2(g) } $




For the reaction $CO_{(g)} + {1 ackslash 2} O_{2(g)} ightarrow CO_{2(g)}$, the enthalpy change (ΔH) is greater than the change in internal energy (ΔE) because the reaction involves a change in the number of moles of gas. At constant temperature and pressure, the enthalpy change includes the pressure-volume work done by the system, making ΔH larger than ΔE.
If $ \triangle H $ is the change in enthalpy and the changes in internal energy accompanying a gaseous reaction




The change in enthalpy (ΔH) can be less than the change in internal energy (ΔE) if the number of moles of the products is less than the number of moles of the reactants. This is because ΔH = ΔE + PΔV, and if the volume decreases (fewer moles of gas), then PΔV is negative, making ΔH less than ΔE.
Enthalpy is an ________property




Enthalpy is an extensive property. Extensive properties depend on the amount of matter in a sample. Since enthalpy is proportional to the amount of substance, it is classified as an extensive property.
Select the correct set of statements/s : I . Work done by the surrounding in case of infinite stage expansion is more than single stage expansion II . Irreversible work is always greater than reversible work III . On an ideal gas in case of single stage expansion and compression system as well as surrounding are restored back to their original states IV . If gas is in thermodynamic equilibrium is taken from state A to state B , by four successive single stage expansions,. Then we can plot 4 points on the P-V indicator diagram




No explanation available.
Hess Law of Heat summation includes




Hess's Law of Heat Summation states that the total enthalpy change of a reaction is the same, regardless of the number of steps the reaction is carried out in. Thus, it includes both the initial reactants and final products. This implies that the enthalpy change is dependent on the initial and final states of the reactants and products.