Final Temp of Water Mixture: 28.46°C

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AI Thread Summary
The discussion revolves around calculating the final temperature of a water mixture, where 25g of water at 10°C is mixed with 40g of water at 80°C. The initial attempt at the solution used the heat transfer equation but resulted in an incorrect final temperature of 28.46°C. A correction was provided, emphasizing the need to properly account for the temperature changes of both water samples. The correct approach leads to a final temperature of 53°C, highlighting the importance of accurately applying the heat transfer principles. The conversation underscores the significance of understanding the concept of heat gained and lost in thermal equilibrium.
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Homework Statement


If 25g of water at a temperature of 10 degrees Celsius is mixed with 40 grams of water at 80 degrees Celsius what is the final temperature of the mixture?

Homework Equations


Qlost + Qgained = 0
Q=mcΔt

The Attempt at a Solution


Attempt 2:
0.025(4186)(x-10) + (0.04)(4186)(x-40) = 0
x = 28.46

I don't know if I'm doing this right...
 
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Durin said:
I don't know if I'm doing this right...

You have the right idea, just remember that delta T = Tf - Ti

So the water at 10 degrees is going to heat to some final temperature T, and the water at 80 degrees is going to cool to the same temperature T

we don't need the specific heat of water since it's common in both terms

(0.025)(10 - x) = (0.04)(x-80)

x = 53 degrees

Also note in your equation - your heat is 40 degrees rather than what the question states - 80 degrees. Perhaps you were thinking of 40g

hope this helps,

cheers
 
Thank you so much!
 
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