Entropy change and work done

In summary, figure 20-29 shows a reversible cycle through which 1.00 mol of a monatomic ideal gas is taken, with given values for pressure and volume. The work done during the cycle can be calculated using the graph, and the energy added during stroke abc can also be calculated using the equation Q=n(Cp)deltaT. The efficiency of the cycle can be determined by calculating the ratio of the work done to the energy added. For an ideal engine operating between the highest and lowest temperatures that occur in the cycle, the efficiency can be either greater or less than the efficiency calculated in (c).
  • #1
tigers4
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Figure 20-29 shows a reversible cycle through which 1.00 mol of a monatomic ideal gas is taken. Assume that p = 2p0, V = 2V0, p0 = 1.13*10^5 Pa, and V0 = 0.0235 m^3.

Fig. 20-29 http://s1142.photobucket.com/albums/n603/bdoneski/?action=view&current=hrw7_20-29.gif"
(a) Calculate the work done during the cycle.
J
(b) Calculate the energy added during stroke abc.
J
(c) Calculate the efficiency of the cycle.
%
(d) What is the efficiency of an ideal engine operating between the highest and lowest temperatures that occur in the cycle? (Note whether this is greater than or less than the efficiency calculated in (c).)
%

Homework Equations


Q=n(Cp)deltaT

The Attempt at a Solution


not sure how to use the graph to calculate anything. I don't know the first step to a solution. Any help would be greatly appreciated
 
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  • #2
nevermind i solved it
 

What is entropy change?

Entropy change is a measure of the disorder or randomness of a system. It is a thermodynamic property that describes the amount of energy that is unavailable for work in a thermodynamic process.

How is entropy change related to work done?

Entropy change is related to work done through the second law of thermodynamics, which states that in any thermodynamic process, the total entropy of a closed system always increases. This means that as work is done on a system, the disorder or randomness of the system increases, leading to an increase in entropy.

What factors affect the entropy change of a system?

The entropy change of a system is affected by several factors, including temperature, pressure, and the number of molecules or particles in the system. Higher temperatures and pressures generally lead to a larger entropy change, while a larger number of molecules can either increase or decrease entropy depending on the specific process.

Can entropy change be negative?

Yes, entropy change can be negative. This occurs when the disorder or randomness of a system decreases, leading to a decrease in entropy. An example of this is when a gas is compressed, as the molecules become more ordered and the entropy decreases.

How is entropy change measured?

Entropy change is measured in units of joules per kelvin (J/K) in the International System of Units (SI). However, it can also be measured in other units such as calories per degree Celsius (cal/°C) or kilojoules per mole-kelvin (kJ/mol•K) depending on the specific application.

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