Calculate the amount of heat

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In summary: C=nRT/PIn summary, the amount of heat to be added to warm 150g of ice from -10C to produce steam at 110C is 12,000 kcal.
  • #1
domyy
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Homework Statement



Calculate the amount of heat to be added to warm 150g of ice from -10C to produce steam at 110C.

Homework Equations



Ice = cice = 0.5cal/gC, L = 80 cal/g.
Water = Cw = 1.0 cal/gC;
Steam = csteam = 0.5 cal/gC; Lv = 540 cal/g

The Attempt at a Solution



I know the answer should be 109.5kcal.

I have found 12,000 cal. BUT I HAVE ABSOLUTELY NO IDEA HOW TO GET TO 109kcal. I JUST NEED SOME DIRECTION.
 
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  • #2


Show how you got 12 kcal.
 
  • #3


Q = mLf = 150g x 80 Cal/g = 12,000
 
  • #4


I know this problem is more complex than that.

Another equation that is possible to use is q=mcdeltat

I remember my professor drawing a graph, with equations for solid, liquid and gas...
I think I am supposed to have that in mind.
 
  • #5


The graph shows increase, then constant, then increase and constant, then increase.
 
  • #6


domyy said:
Q = mLf = 150g x 80 Cal/g = 12,000

That's just a melting part.

domyy said:
Another equation that is possible to use is q=mcdeltat

I remember my professor drawing a graph, with equations for solid, liquid and gas...
I think I am supposed to have that in mind.

domyy said:
The graph shows increase, then constant, then increase and constant, then increase.

And that's a good hint at equations that should be used. Have you copied that graph?

What must happen to the ice so that water becomes a steam?
 
  • #7


There are 5 processes at work here. First, you must heat the water from -10C to 0C. Then more energy must be provided to turn the 0C ice to 0C water. Then you must heat the water from 0C to 100C. Then you must turn the 100C water to 100C steam. Finally, you heat the steam to the final 110C. Phase changes require energy as well as temperature changes. The equations you have can be used to determine exactly how these processes occur.
 
  • #8


One of the solutions would be q=mlf
=150g x 540=81,000?
 
  • #9


I will also have q=150g x 80cal/g = 12,000
 
  • #10


Am i doing it right? I will have to sum the values later?
 
  • #11


You can sum them all as the last step.
 
  • #12


Oh yes I already got the answer. Thanks a lot!
 
  • #13


Can I ask you something? I read that as bubbles rise in deep column of water the diameter increases. Could explain this more clear to me?
 
  • #14


Please don't hijack threads, if you have a new question - start a new thread.

PV=nRT, P=ρh
 

1. How do you calculate the amount of heat in a substance?

The amount of heat in a substance can be calculated using the equation Q = mCΔT, where Q is the amount of heat, m is the mass of the substance, C is the specific heat capacity of the substance, and ΔT is the change in temperature.

2. What is specific heat capacity and how does it affect the calculation of heat?

Specific heat capacity is the amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius. It is a constant value that varies for different substances. It is used in the calculation of heat to determine how much heat is needed to change the temperature of a specific substance.

3. Can you calculate the amount of heat in a chemical reaction?

Yes, the amount of heat in a chemical reaction can be calculated using the equation Q = mCΔT, where Q is the amount of heat, m is the mass of the substance, C is the specific heat capacity of the substance, and ΔT is the change in temperature. The mass and specific heat capacity of each substance involved in the reaction must be known in order to calculate the heat.

4. How does the amount of heat affect the temperature of a substance?

The amount of heat is directly proportional to the change in temperature of a substance. This means that the more heat that is applied to a substance, the greater the change in temperature will be. However, this relationship can be affected by other factors such as the specific heat capacity and the mass of the substance.

5. Is the calculation of heat affected by the state of matter of a substance?

Yes, the state of matter of a substance can affect the calculation of heat. This is because different substances have different specific heat capacities and different states of matter have different specific heat capacities. For example, liquid water has a higher specific heat capacity than solid ice, meaning it requires more heat to change its temperature by the same amount.

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