How do I calculate the energy needed to convert ice at -20C to steam at 110C?

Click For Summary
SUMMARY

The discussion focuses on calculating the energy required to convert 9 grams of ice at -20°C to steam at 110°C. The relevant specific heat capacities and enthalpies of fusion and vaporization are provided: C for ice is 2.06 J/g°C, C for water is 4.18 J/g°C, C for steam is 2.02 J/g°C, Hf of ice is 334 J/g, and Hv of water is 2260 J/g. The initial calculation presented totals 27,795 J, but the participant expresses confusion regarding the correctness of the solution and seeks step-by-step guidance to clarify the processes involved.

PREREQUISITES
  • Understanding of specific heat capacity
  • Knowledge of enthalpy of fusion and vaporization
  • Familiarity with the phase changes of water
  • Basic algebra for energy calculations
NEXT STEPS
  • Review the concept of specific heat capacity in thermodynamics
  • Study the phase changes of water, including melting and vaporization
  • Learn how to apply the formula Q = mcΔT for various phases
  • Practice similar energy calculation problems involving phase changes
USEFUL FOR

This discussion is beneficial for students studying thermodynamics, particularly those tackling energy calculations in chemistry or physics. It is also useful for educators looking for examples of phase change problems.

SimplySydney
Messages
1
Reaction score
0

Homework Statement


Calculate the energy need to change 9 g of ice at -20 degrees Celsius to steam at 110 degrees Celsius. (C for ice=2.06 J/g, C for water=4.18 J/g, C for steam=2.02 J/g, Hf of ice=334 J/g, Hv of water=2260 J/g)


Homework Equations


Q=hv / Q=mHf / Q=mc(delta)t


The Attempt at a Solution


Q=(9 X 2.06 X 20) + (9 X 334) + (9 X 2.06 X 110) + (9 X 2260) + (9 X 2.06 X 110) = 27795 J

Okay so I did this problem in class with a group, but looking back on it, I think it is wrong. But I'm not sure! I'm just very very very confused on what to do. Step by step instructions would help! And the answer has to be in joules not calories. Thanks! :)
 
Physics news on Phys.org
Hi SimplySydney, welcome to PF. What are the processes that the material (originally a solid at -20C) has to go through to reach the vapor form at 110C? It looks like the first two terms represent the energy needed to heat ice to 0C and the energy needed to melt it to form liquid at 0C. What do the other terms represent?
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
5K
Replies
1
Views
4K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 1 ·
Replies
1
Views
11K
Replies
3
Views
5K
Replies
2
Views
6K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
1
Views
1K