PV diagrams monatomic ideal gas

In summary, the conversation discusses finding the total work done, change in internal energy, and heat flow for an ideal gas undergoing a process from state A to state D on a PV diagram. The total work is calculated by using the formula W = Pi(Vf-Vi) for the constant pressure and constant temperature paths. However, there may be an error in the calculation as the pressure is not constant during the entire process. Further clarification is needed on the pressure and volume relationship during the isothermal process.
  • #1
lalahelp
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Homework Statement


Suppose a monatomic ideal gas is changed from state A to state D by one of the processes shown on the PV diagram. (Let V1 = 4.80 L and P1 = 3.30 atm.)

(a) Find the total work done on the gas if it follows the constant pressure path A−E followed by the constant temperature path E−D.
(b)Calculate the total change in internal energy of the gas during the entire process.
(c)Calculate the total heat flow into the gas


2. W=pi(vf-vi)
(1.01e5)(3.3)(9.6-4.8)(.001)=1599.84 J
(1.01e5)(6.6+3.3)(19.2-9.6)(.001)= 4799.5 J
=6399 J

Why is my work wrong??
 

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  • #2
lalahelp said:

Homework Statement


Suppose a monatomic ideal gas is changed from state A to state D by one of the processes shown on the PV diagram. (Let V1 = 4.80 L and P1 = 3.30 atm.)

(a) Find the total work done on the gas if it follows the constant pressure path A−E followed by the constant temperature path E−D.
(b)Calculate the total change in internal energy of the gas during the entire process.
(c)Calculate the total heat flow into the gas


2. W=pi(vf-vi)
(1.01e5)(3.3)(9.6-4.8)(.001)=1599.84 J
(1.01e5)(6.6+3.3)(19.2-9.6)(.001)= 4799.5 J
=6399 J

Why is my work wrong??
I am having trouble following your reasoning.

First, why would W = Pi(Vf-Vi) if the pressure is constant at 2Pi for A-E?

Second, why would you use 3Pi for the E-D path? Is the pressure constant during that process? What is the relationship between P and V during an isothermal process?

AM
 

FAQ: PV diagrams monatomic ideal gas

What is a PV diagram for a monatomic ideal gas?

A PV diagram is a graphical representation of the relationship between pressure (P) and volume (V) of a monatomic ideal gas. It is a plot of pressure on the y-axis and volume on the x-axis, with each point on the graph representing a specific state of the gas.

How is a PV diagram used to analyze the behavior of a monatomic ideal gas?

A PV diagram can be used to analyze the behavior of a monatomic ideal gas by observing the changes in pressure and volume as the gas undergoes different processes, such as isothermal, isobaric, and adiabatic processes. It can also be used to calculate the work done by the gas and the change in internal energy.

What does the shape of a PV diagram for a monatomic ideal gas indicate?

The shape of a PV diagram for a monatomic ideal gas can indicate the type of process the gas is undergoing. For example, a horizontal line represents an isobaric process, a vertical line represents an isothermal process, and a curved line represents an adiabatic process.

How does the ideal gas law relate to PV diagrams for monatomic gases?

The ideal gas law, PV = nRT, relates to PV diagrams for monatomic gases by showing the relationship between pressure, volume, temperature, and the number of moles of gas. This law can be used to calculate the pressure or volume of a gas at a specific state on the PV diagram.

Can PV diagrams be used for non-ideal gases?

While PV diagrams are commonly used for ideal gases, they can also be used for non-ideal gases. However, the ideal gas law may not accurately represent the behavior of these gases, so other equations, such as the van der Waals equation, may need to be used to analyze the PV diagram.

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