Calculate Heat of Reaction for 50g of Water at 80°C

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To calculate the heat absorbed by the room temperature water when 50g of hot water is added, the correct mass to use is 50g, not 100g. The equation for heat transfer, Q = mc(dT), should be applied using the mass of the room temperature water alone. The temperature change in the bowl indicates that the heat absorbed is due solely to the 50g of room temperature water. Therefore, the final calculation should reflect this mass to determine the heat absorbed accurately. The discussion emphasizes the importance of recognizing the specific mass involved in the heat transfer process.
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Homework Statement


Hi
Lets say I heat 50g of water to 80°C. I take another 50g of room temperature water and put it in a bowl.

Then I add this 50g of heat water to the bowl, the temperature in the bowl goes from 25°C to 48°C.

What is the amount of heat absorbed by the room temperature water?


Homework Equations



Is it
Q = (50g)(4.18 J/(g*k))(48-25)
or
Q = (100g)(4.18 J/(g*k))(48-25)

The Attempt at a Solution



Do you add the solution of water in the mass or just use 50g=mass in the equation?
 
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aDVnatgae said:
What is the amount of heat absorbed by the room temperature water?

What is the mass of the room temperature water? 50g or 100g?
 
Borek said:
What is the mass of the room temperature water? 50g or 100g?

I add the 50g of hot water to 50g of water in the bowl. Wondering when calculation the
Q=mc(dT)
should the mass be 100 or 50
 
You have 50 g of the room temperature water and 50 g of hot water. What is the mass of the room temperature water?

This is like one of those stupid joke questions kids ask - answer is so obvious nobody sees it.

Yes, it is THAT simple.
 
Borek said:
You have 50 g of the room temperature water and 50 g of hot water. What is the mass of the room temperature water?

This is like one of those stupid joke questions kids ask - answer is so obvious nobody sees it.

Yes, it is THAT simple.

What is the mass of the room temperature water?
answer is 50g
 
Borek said:
You have 50 g of the room temperature water and 50 g of hot water. What is the mass of the room temperature water?

This is like one of those stupid joke questions kids ask - answer is so obvious nobody sees it.

Yes, it is THAT simple.

K. What I am asking to you is when I add hot water in the bowl to temperature of bowl changes from 25°C to 48°C. The total mass of water in the bowl is 100g.

What is the amount of heat absorbed by the room temperature water?
So do I use 50g or 100g as a mass?
 
There is 50 g of the room temperature water, so 50 g of the room temperature water can absorb a heat.

Imagine you have not mixed these samples of water, but they were isolated by a thin metal sheet so that they could not mix, but the heat could easily flow. Final temperature is identical in both cases, but it should be obvious why there is 50 g of the room temperature water absorbing heat.

Note that so far we were all the time discussing exactly the same problem, you just couldn't make a connection. If there is 50 g of the room temperature water there is 50 g of water that can absorb heat.
 
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