Please help with my 3 questions

  • Thread starter truckerron1
  • Start date
In summary, the conversation discusses three questions regarding gas and energy, PV diagrams, and engine efficiency. The first question deals with calculating the amount of energy needed for a 12 K temperature increase in 180 g of neon gas. The second question involves constructing a PV diagram for two different scenarios, while the third question asks for the highest possible exhaust temperature of an engine with efficiency 27% operating at 420°C.
  • #1
truckerron1
8
0
i have 3 questions that i need help with

Consider 180 g of neon gas. How much energy would it have to absorb to experience a temperature increase of 12 K?

Construct a PV diagram for each of the following. (a) A gas begins with a volume of 14 L under pressure of 3 atm. The gas first undergoes an isobaric compression to a volume of 6 L. Next, the gas experiences an isothermal expansion back to a volume of 14 L. (b). A gas undergoes a cyclic process consisting of two isochoric processes and two isobaric processes.

A particular engine having efficiency 27% operates at temperature 420C. What is its highest possible exhaust temperature?

thanks ron
 
Physics news on Phys.org
  • #2
I will just help you with the first question.
Consider this formula:

[tex]Q = m.c.dT[/tex]

m= 180 g
c= ? -> you have to check on a table
dT = 12 K

Now, it's up to you. :biggrin:
 
  • #3


1. To calculate the energy needed for a temperature increase of 12 K for 180 g of neon gas, we would use the formula Q = mcΔT, where Q is the energy, m is the mass of the gas, c is the specific heat capacity, and ΔT is the change in temperature. In this case, we would need to know the specific heat capacity of neon gas, which is 1.03 J/gK. Plugging in the values, we get Q = (180 g)(1.03 J/gK)(12 K) = 2217.6 J of energy needed for the temperature increase.

2. (a) The PV diagram for this process would look like a rectangle, with the initial point at (3 atm, 14 L) and the final point at (3 atm, 6 L). The area of this rectangle represents the work done on the gas during the isobaric compression. The second part of the process, the isothermal expansion, would appear as a horizontal line connecting the final point (3 atm, 6 L) to the initial point (3 atm, 14 L). This line represents no work being done on the gas, as the pressure remains constant.

(b) For this cyclic process, the PV diagram would look like a square, with two vertical lines representing the isochoric processes and two horizontal lines representing the isobaric processes. The area inside the square represents the net work done on the gas during the cycle.

3. To find the highest possible exhaust temperature for an engine with 27% efficiency operating at 420°C, we can use the Carnot efficiency formula, η = 1 - (Tc/Th), where η is the efficiency, Tc is the temperature of the cold reservoir (in Kelvin), and Th is the temperature of the hot reservoir (in Kelvin). Rearranging the formula to solve for Th, we get Th = Tc/(1-η). Plugging in the values, we get Th = (420+273)/0.73 = 825.3 K, or approximately 552.3°C as the highest possible exhaust temperature.
 

1. What are the three questions you need help with?

The three questions that I need help with typically vary depending on the specific situation or project I am working on. However, they generally revolve around gathering data, analyzing results, and drawing conclusions in a scientific and objective manner.

2. Can you give more information about the context of the questions?

In order for me to provide accurate and helpful answers, it would be helpful to know the specific field of science or research that the questions pertain to, as well as any relevant background information or details about the experiment or study being conducted.

3. How can I ensure that my questions are clear and concise?

When formulating any scientific question, it is important to use precise and specific language, avoiding any ambiguity or vagueness. It can also be helpful to have another scientist or peer review the questions to ensure they are clear and unbiased.

4. Have you considered potential confounding variables in your questions?

As a scientist, it is crucial to consider and account for any potential confounding variables in order to ensure the validity and reliability of the results. This may involve conducting control experiments or adjusting the methods to minimize the impact of any potential confounders.

5. What resources or references do you recommend for finding answers to your questions?

There are many reputable scientific journals, books, and online databases that can provide valuable information and insights for answering scientific questions. It is important to critically evaluate the credibility and relevance of any sources used in research.

Similar threads

  • Introductory Physics Homework Help
Replies
1
Views
113
  • Introductory Physics Homework Help
Replies
2
Views
754
Replies
11
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
9
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
868
Back
Top