How Do You Calculate Energy Changes in Water Phase Transitions?

In summary, the conversation discusses questions related to energy and phase changes of water. The first question asks about the amount of energy released when steam condenses and cools to water. The second question involves adding heat to melt a block of ice. The third question asks about the form of water after heat is removed from steam. The final question involves calculating the temperature of remaining water after some has evaporated. The solution involves using the equation Q=mcT and looking up values for heat capacity and specific heat capacity.
  • #1
stupefy07
3
0

Homework Statement



1. What amount of energy is released whan 10g of steam at 100 degrees C condenses and then cools to water at 0 degrees C?

2. 1840 calories of heat is added to a 300g block of ice at 0 degrees C. what amount of ice melts?

3. 3600 calories of heat is removed from 5g of steam initially at 100 degrees C. In what form is the water in the end?

4. Consider 35g of water at 1000C. If 4g rapdily evaporates, what will be the temperature of the remaining 31 grams of water?

Homework Equations



Q = mcT

The Attempt at a Solution



1. it takes 540 then 100 then 80...do i add those up and multiply by 10?
2. no idea
3. no idea
4. i know evaporation is a cooling process so there will be less heat in the 31 grams of water...but nothing else
 
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  • #2
Use the relation between heat capacity, mass, temperature and heat.
Look up values for heat capacity, specific heat capacity and latent heat of fusion/melting for water.
 

1. What is a phase change in physics?

A phase change in physics refers to the physical transformation of a substance from one state to another, such as from solid to liquid or from liquid to gas. This process is also known as a change in state or a change in phase.

2. What are the different types of phase changes?

There are four main types of phase changes: solidification (melting), vaporization (boiling), condensation (freezing), and sublimation (deposition). These changes occur due to changes in temperature or pressure.

3. How do I calculate the amount of heat needed for a phase change?

The amount of heat needed for a phase change can be calculated using the formula Q = mL, where Q is the amount of heat, m is the mass of the substance, and L is the latent heat of the substance. The latent heat is specific to each substance and can be found in a reference table.

4. What is the difference between specific heat and latent heat?

Specific heat refers to the amount of heat needed to raise the temperature of a substance by 1 degree Celsius, while latent heat refers to the amount of heat needed to change the phase of a substance without changing its temperature. Specific heat is measured in J/(kg·K), while latent heat is measured in J/kg.

5. How does a phase change affect the behavior of molecules?

During a phase change, the behavior of molecules changes as they rearrange themselves and gain or lose energy. In solids, molecules are tightly packed and vibrate in place. In liquids, molecules have more space to move around and can slide over each other. In gases, molecules are far apart and move freely in all directions.

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