Heat Needed to raise Water to Steam: A Math Problem

In summary, to make steam, 5.8 X105J of heat must be added to 0.2 kg of water with an initial temperature of 50oC. To bring the water to 100oC, an additional 41860 J of heat must be added. To convert the water to steam, an additional 452000 J of heat must be added. After the conversion, 86140 J of the original 5.8 X105J of energy has not been turned into internal energy. The change in temperature of the system is 216oC. The final temperature of the system can be approximated to be around 340oC using the specific heat for steam of 4235 J/kg.
  • #1
mattmannmf
172
0
To make steam, you add 5.8 X105J of heat to 0.2 kg of water with an initial temperature of 50oC.

(a) What amount of heat must be added to the water to bring its temperature to 100oC?
41860

(b) What amount of additional heat must be added to this 100oC water to convert it to steam?
452000

(c) How much of the original 5.8 X105J of energy added has not been turned into internal energy after all the water has been converted to steam?
86140

(d) What is the change in temperature of the system after all the water has turned to steam?

(e) What is the final temperature of the system?

So i am just stuck on d and e. not sure how to find the final temperature change... any help wanted
 
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  • #2
i found that d is 216... so i actually need help on e
 
  • #3
mattmannmf said:
i found that d is 216... so i actually need help on e

You will want the specific heat for steam. Above 100° it is still close to 4219 to 4250 J/kg at 120°. You can probably use 4235 as a good figure for determining the additional temp rise.

http://www.engineeringtoolbox.com/water-thermal-properties-d_162.html
 

1. What is the purpose of calculating the heat needed to raise water to steam?

The purpose of this calculation is to determine the amount of energy (in the form of heat) required to convert water from its liquid state to steam. This is important in various industrial processes such as power generation, food processing, and chemical reactions.

2. How is the heat needed to raise water to steam calculated?

The calculation involves using the specific heat capacity of water, which is the amount of heat required to raise the temperature of one gram of water by one degree Celsius. The formula used is Q = m x c x ΔT, where Q is the heat needed, m is the mass of water, c is the specific heat capacity of water, and ΔT is the change in temperature.

3. What factors can affect the amount of heat needed to raise water to steam?

The main factors that can affect the amount of heat needed include the initial temperature of the water, the pressure at which the water is being heated, and any impurities or additives in the water that may change its specific heat capacity.

4. Is the heat needed to raise water to steam a constant value?

No, the amount of heat needed can vary depending on the factors mentioned above. For example, if the initial temperature of the water is higher, less heat will be needed to raise it to steam. Similarly, if the pressure is higher, more heat will be needed.

5. Can this calculation be applied to other substances besides water?

Yes, the same calculation can be applied to other substances, but the specific heat capacity used will be different. Each substance has its own specific heat capacity, which is why the calculation must be adjusted accordingly.

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