How to Solve the 4th Thermodynamics Question on Heat Capacity?

[DrVirz]

Homework Statement

Hi all, please see uploaded pics. I can do the first 3 questions but can't get my head around the 4th. Any help is appreciated.

 

[Delta2]

The rate at which heat is lost by the air [itex]P_{air}[/itex], equals to minus the rate [itex]P_{water}[/itex]at which heat is absorbed by the water. So it will be [itex]P_{air}=-P_{water}[/itex].

[itex]P_{air}=C_{air}\dot{m}_{air}(47-167)[/itex], [itex]P_{water}=C_{water}\dot{m}_{water}(40-35)[/itex]

 

[DrVirz]

Hi Delta,

What have you denoted as C?

 

[Delta2]

Its the specific heat capacity. For water is 4.17 and for air around 1.01 at the temperatures of this problem.

 

[DrVirz]

I thought it was the specific heat capacity but I can only find the Cv/Cp for water in any of the tables from my text which was confusing me a bit.

Cheers for the help!

 

[Chestermiller]

I thought it was the specific heat capacity but I can only find the Cv/Cp for water in any of the tables from my text which was confusing me a bit.

Cheers for the help!

It's liquid water. What is the heat capacity of liquid water?

Chet

 

[DrVirz]

It's liquid water. What is the heat capacity of liquid water?

Chet

Sorry in my previous post i meant to say CANT find the Cv/Cp value for water in any of my tables.

 

[Chestermiller]

Sorry in my previous post i meant to say CANT find the Cv/Cp value for water in any of my tables.

The heat capacity of liquid water is 4.18 kJ/kg C. Did you not see Δ²'s post # 4? Are you saying you never had this in freshman physics?

Chet

 

[DrVirz]

The heat capacity of liquid water is 4.18 kJ/kg C. Did you not see Δ²'s post # 4? Are you saying you never had this in freshman physics?

Chet

Yes I did see that in Delta's post. I am just saying, naturally, I refer to the tables for my data values and when I didn't come across a value for water it threw me off. I thought I had done something wrong. That's what happens when you have been studying all day I guess, time to take a rest.

 

[Chestermiller]

Yes I did see that in Delta's post. I am just saying, naturally, I refer to the tables for my data values and when I didn't come across a value for water it threw me off. I thought I had done something wrong. That's what happens when you have been studying all day I guess, time to take a rest.

All I did was Google "heat capacity of water."

Chet