July 8, 2016--11. Please help -- Please show me step by step. Please and thank y
ID: 1011670 • Letter: J
Question
July 8, 2016--11.
Please help -- Please show me step by step. Please and thank you very much. ***Please give me some explanation -- Thank you so much and have a wonderful weekend.
An ideal gas is expanded to twice its initial volume by reducing the pressure 60% (ie ½-2y, P2-0.4P.). Circle all statements that are true. (a) The process is isothermal (b) The process is polytropic (c) Heat is added during the expansion, Qin>0 (d) Temperature decreases (e) Final temperature, T, is less than if it had been adiabatio (f) Polytropic exponent, n, is less than unity (i.e. nExplanation / Answer
A) considered a gas that is allowed to slowly excape from a container immersed in a constant temperature bath. As the gas expands it does work on the surroundings and therefore tends to cool, but the thermal gradient that result causes heat to pass into gas from the surroundings to exactly compensate for this change. This is called isothermal expansion. In an isothermal process the internal energy remains constant and we can write first law as 0=q+w or q=_w . Illustrating that the heat flow and work done exactly balance each other. An isothermal process is a change of a system, in which the temperature remains constant . Delta T=0.
B) a polytropic process is a thermodynamics process that obeys the relation. Pvn=c. Where p is pressure, v is the specific volume, n is the polytropic index and c is constant. The polytropic process equation can describe multiple expansion and compression process which include heat transfer.
V) because this process is isothermal process . In this process heat or temperatures remains constant . For expanding the gas it needed the heat from the surroundings . Therefore we can add the heat during the expansion. Therefore it shows equation Qn>0.
D) because an isothermal process is a change of system, in which the temperature remains constant .Delta T=0. This typically occurs when a system is contact with an outside thermal reservoir. Therefore in this process heat decreases.
E) an adiabatic process is one that occurs without transfer of heat between a thermodynamics system and its surroundings.In an adiabatic process energy is transferred only as work. Some chemical and physical process occurs so rapidly that they may be conveniently described by the adiabatic approximation meaning that there is not enough time for the transfer of energy as heat to takes place. Hence final temperatures T2 is less.
F) because it is equivalent to an isothermal process, under the assumption of ideal gas law, since then pv=nrt. Therefore polytropic exponent,n, is less than unity.
G) because this process is based on ideal gas. The equation for ideal gas is, pv=nrt.Where people is pressure, v is volume, n is amount of substance,r is gas constant, t is absolute temperature. Therefore pv=rt equation is valid at both initial and final state.
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