Why Did My Calculation of Temperature Change Result in the Wrong Answer?

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Homework Help Overview

The discussion revolves around a problem in thermodynamics related to calculating temperature change in water when a specific amount of heat is lost. The original poster is attempting to determine the temperature change when 10 kg of water loses 232 kJ of heat.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the formula for temperature change but questions their calculation after arriving at an unexpected result. Some participants suggest checking unit consistency and the inclusion of signs in calculations.

Discussion Status

Participants are exploring the calculation process, with some providing guidance on unit conversion and the correct application of the formula. There is no explicit consensus on the original poster's error, but suggestions for clarification and correction are present.

Contextual Notes

The original poster's calculation involves converting kJ to joules and applying the specific heat capacity of water. There is a mention of potential confusion regarding unit consistency and the handling of energy signs.

punk_rawk_jazz
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Does anyone know why I end up with the wrong answer?
The question is:
Determine the temperature change: 10 kg of water loses 232 kJ or heatQUOTE]

I went delta q is equal to m c delta t, the derived the equation delta t is equal to delta q divded by mc. I therefore did the math as 232 kJ divided by (10 kg times 4.2 x 10 ^3 j/kg C) and got 9.7 x 10 ^4, when the answer was supposed to be 5.5. Does anyone know what I did wrong??


Thank you in advance
 
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Make sure you are consistent in units. Also remember to include signs in your calculations to indicate gain/loss of energy.
 
Hope this helps

Firstly just change the 232 kJ into joules so you that have 232000 J.

q = mc delta t
232000 = 10 * 4200 * delta t
delta t = 232000/10*4200
delta t = 232000/42000
delta t = 5.5
 
Was there any particular reason why you posted this twice?
 
Nope I just mest up...
 

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