Temperature and Heat - what am i doing wrong?

  • Thread starter Thread starter grandprix
  • Start date Start date
  • Tags Tags
    Heat Temperature
AI Thread Summary
To convert 9 kg of ice at 0°C to steam at 100°C, three processes must occur: melting the ice, heating the water, and vaporizing the steam. The heat required to melt the ice is calculated using the latent heat of fusion (lf), which is 79500 cal/kg, resulting in 715500 cal for 9 kg of ice. Next, the water must be heated from 0°C to 100°C using the specific heat capacity (c) of water, which is 1000 cal/kg°C, requiring an additional 900000 cal. Finally, to convert the water at 100°C to steam, the latent heat of vaporization (lv) is used, amounting to 4860000 cal for 9 kg. The total heat needed is 6465000 cal, or 6465 kcal.
grandprix
Messages
28
Reaction score
0

Homework Statement



lf = 79500 cal/kg ,
lv = 5.4 × 105 cal/kg ,
c = 1000 cal/kg ◦ C.

9 kg of ice at 0◦C is converted to steam at
100◦C.
How much heat is needed? Answer in units
of kcal.


Homework Equations



q=mct

The Attempt at a Solution



100*9kg + 79.5 + 540 = 1519.5

I am getting this wrong I don't know why
 
Physics news on Phys.org
Can you explain what each term in your attempted solution means? They don't seem to make sense. They don't match the numbers given in the problem? It would be helpful if you explained what you were doing.

Also, what three processes (involving heat) have to occur in order to get from ice at 0C to steam at 100C?
 
If lf is 79500 cal/kg, and you have 9 kg of ice, then how much energy is required to melt the ice?

Hint: the answer it not 79.5.

Also, what is the value of c for water?
 
I got the answer! Thanks for your help.
 
Thread 'Voltmeter readings for this circuit with switches'

Thread 'Voltmeter readings for this circuit with switches'

TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
View full post »
Thread 'Correct statement about a reservoir with an outlet pipe'

Thread 'Correct statement about a reservoir with an outlet pipe'

The answer to this question is statements (ii) and (iv) are correct. (i) This is FALSE because the speed of water in the tap is greater than speed at the water surface (ii) I don't even understand this statement. What does the "seal" part have to do with water flowing out? Won't the water still flow out through the tap until the tank is empty whether the reservoir is sealed or not? (iii) In my opinion, this statement would be correct. Increasing the gravitational potential energy of the...
View full post »

Similar threads

Heat Question -- Temperature rise of a hiker on a long hike
Replies
1
Views
2K
I try to solve a thermodynamics problem on heat transfer
Replies
3
Views
2K
Calculating Equilibrium Temperature of Ice and Water Mixture
Replies
1
Views
2K
1 kg of ice at -20°C is mixed with 1kg steam at 200°C......
Replies
9
Views
7K
How much heat is needed for converting 7 kg of ice to steam?
Replies
6
Views
6K
Mass of Ice required to achieve a certain final Temperature
Replies
3
Views
2K
Finding the Value of M in a Physics Homework Problem
Replies
12
Views
2K
How Much Steam Is Needed to Heat Water from 24°C to 90°C?
Replies
1
Views
3K
Thermodynamics adding ice to water problem with latent heat
Replies
1
Views
3K
Thermodynamics- conservation of heat and energy
Replies
13
Views
2K

Hot Threads

Recent Insights

Back
Top