Heating Water at 90C: Why It Takes Longer Than Lower Temps

In summary, heating water at 90C takes longer due to the increase in specific heat capacity. The rate of heat transfer is slower at 90C because of the smaller temperature gradient. The phase change of water from liquid to gas at 90C also contributes to the longer heating time. The type of container used and atmospheric pressure can also affect the heating time at 90C. Materials with higher thermal conductivity and higher atmospheric pressure can lead to faster heating times.
  • #1
darkmagic
164
0
Why heating water at 90C takes longer than heating water at lower temperatures such as 70C?
 
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  • #2
I never heard of this before. But I can't give you an answer since I don't know much about heat transfer.
 
  • #3
Because a lower initial temperature requires more energy to reach a set point? Water heats linearly (generally) between 0C and 100C (STP) ... 4186j/C or so.
 
  • #4
You need to show your work. We cannot give you answers.

Why do you think it takes longer?
 
  • #5
does the specific heat capacity has something to do with this?
 

1. Why does it take longer to heat water at 90C compared to lower temperatures?

Heating water at 90C takes longer because the specific heat capacity of water increases as the temperature rises. This means that it takes more energy to raise the temperature of water at 90C compared to water at lower temperatures.

2. How does the heat transfer process differ at 90C compared to lower temperatures?

The rate of heat transfer is slower at 90C compared to lower temperatures because the temperature difference between the water and its surroundings is smaller. This results in a smaller temperature gradient, which leads to a slower transfer of heat.

3. Is there a specific reason why water takes longer to heat at 90C?

Yes, at 90C water undergoes a phase change from liquid to gas, which requires a significant amount of energy. This energy is used to break the hydrogen bonds between water molecules and convert them into water vapor, resulting in a slower heating process.

4. Does the type of container used to heat water at 90C affect the heating time?

Yes, the type of container can affect the heating time of water at 90C. Materials with higher thermal conductivity, such as metal, will transfer heat more efficiently and therefore heat the water faster compared to materials with lower thermal conductivity, such as glass.

5. Can the atmospheric pressure also play a role in the heating time of water at 90C?

Yes, atmospheric pressure can affect the boiling point of water, which in turn can impact the heating time at 90C. Higher atmospheric pressure can increase the boiling point of water, making it take longer to reach 90C and therefore increasing the overall heating time.

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