Molar change in solution - Problem, tried solving dont understand

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The discussion revolves around calculating the temperature rise when dissolving 4.0g of NaOH in 50mL of water. The initial temperature is 19.5°C, and the final temperature should be 37.0°C. The participant calculated the molar enthalpy change of solution as 36.575 kJ/mol but is confused about the resulting temperature increase. Clarification is sought regarding the correct interpretation of the molar enthalpy value, specifically whether it is 36.6 kJ or 36600 kJ. The calculations indicate a misunderstanding in the mole conversion and energy exchange, leading to an incorrect final temperature estimation.
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Homework Statement



How many degrees(Celsius) would the temperature rise if 4,0g of NaOH was initially dissolved in 50mL of water.

Homework Equations



Calculate the molar enthalpy change of solution based on this information:

- 4g NaOH(s) gets dissolved in 250mL of water, and the temperature rose from 19,5 to 23.0 Celsius.
- 4.18 J to raise temperature in 1 gram of water 1 Celsius.
- Water density: 1,0g/mL.
- No energy was exchanged with the surroundings before the temperature change was measured.

I solved this and ended up with 36,575 kJ/mol

The Attempt at a Solution



Here is what I`ve tried:

50ml of water = 50 grams
Molar mass of water: 18,016 g/mol

50/18,016= 2,7753 mol

2,7753 mol * 36,575 kJ/mol= 101kJ

101kJ * 1000= 101000 J

101000/4,18 J/g * Celsius=24162

24162/1000=24,16 Celsius ?

19,5+24,16= 43 Celsius??

I don't understand?
The correct answer is from 19,5 to 37.0 Celsius.
 
Last edited:
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Gold said:
I solved this and ended up with 36,575 kJ/mol

Moles of what?

Do you mean 36.6 kJ or 36600 kJ?
 

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