Thermodynamics ice cube question

Click For Summary
SUMMARY

The discussion focuses on calculating the energy required to transform a 40.0 g ice cube from -8.0°C to steam at 108°C. The process involves multiple stages: heating the ice from -8°C to 0°C, phase change from ice to water, heating the water from 0°C to 100°C, phase change from water to steam, and finally heating the steam from 100°C to 108°C. The relevant equations include the specific heat equation (q=mct) for temperature changes and the latent heat equation (Q=mL) for phase changes. Participants confirm that the total energy is the sum of energies calculated for each stage.

PREREQUISITES
  • Understanding of specific heat capacity (q=mct)
  • Knowledge of latent heat (Q=mL)
  • Familiarity with phase changes (solid to liquid to gas)
  • Basic thermodynamic principles
NEXT STEPS
  • Calculate specific heat capacities for water and ice
  • Explore detailed examples of latent heat calculations
  • Study phase change diagrams and their applications
  • Learn about the thermodynamic properties of steam
USEFUL FOR

Students studying thermodynamics, physics educators, and anyone needing to understand energy transformations in phase changes.

physics_geek
Messages
82
Reaction score
0

Homework Statement


How much energy is required to change a 40.0 g ice cube from ice at -8.0°C to steam at 108°C?


Homework Equations


q=mct


The Attempt at a Solution


i remember one of our TAs going over something like this a long time ago..I think i have to like add up all the energies from the ice going to like 0 C then to like 100C and then 108 C??

can someone help me out
 
Physics news on Phys.org
ok tell me if I am correct
add up all the energy from ice going from -8 to 0
0 to 100 and then 100 to 108?

am i even close?
 
Yes, you are. Now you have to also consider the energy required to change phase (ice to water, water to steam).
 
umm I am not sure what that means
 
Consider: http://www.splung.com/heat/images/latentheat/phasechange.png and also the URL I gave you in my first post.

We separate this problem into stages:

Energy is required to raise the temperature of the solid, in this case the ice, from -8 to 0 degrees celsius. This is stage A-B.

Energy is then required to change phase from ice to water. At this point the temperature remains the same. This is stage B-C.

Once again, energy is required to raise the temperature from 0 to 100 degrees celsius. This is stage C-D.

The water then changes state again to steam. This is another phase change. This is stage D-E.

Finally, the temperature of the steam is raised by 8 degrees to 108 degrees celsius. This is stage E-F.

So, to calculate the energy required to raise 40g of ice from -8 to 108 degrees celsius we must use two equations. One to calculate the energy required to change phase at stages B-C and D-E, and another to calculate the energy required to raise the temperature at stages A-B, C-D and E-F.

The latent heat equation is:

Q=mL

and the other equation required is the one you've already specified.
 

Similar threads

Replies
29
Views
1K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K
Replies
10
Views
2K
Replies
7
Views
2K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K