What Are the Units of Mass and Heat Quantity in Thermochemistry?

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The discussion centers on the calculation of heat quantity in thermochemistry, specifically using the formula Q = mass × specific heat × change in temperature. The correct units for mass are grams (g), while heat quantity is measured in joules (J) or kilojoules (kJ). A user posed a question regarding the calculation of liberated heat when mixing 50 ml of diluted acid and base, resulting in a temperature change from 18.2°C to 21.3°C. The correct calculation yields 1.298 kJ, contradicting a book's erroneous answer of 1295.8 kJ.

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ph_lover3294
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hi for u all

i want to ask a question in a thermochemistry about the law of

quantity of heat = mass . specefic heat . change in temp

firstly . i want to know the units of (mass ) and (heat quantity) in this law
(gm , ml , liter)...(joules,kj)
Q: on adding 50 ml of diluted base on 50 ml of diluted acid in isolated cal. the temp. of the solution rises from 18.2 to 21.3 degree
calculate the liberated heat

thanks ...i wish u answer me quickly ...

bye
 
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ph_lover3294 said:
i want to know the units of (mass ) and (heat quantity) in this law (gm , ml , liter)...(joules,kj)

ml and liter are not units of mass, but units of volume.

Exact units used don't matter. You need to use units of mass, units of temperature and specific heat that is expressed using these units and units of energy that you want your answer to be in.
 
Last edited:


thank u for your answer

but i want to know the answer of the above question
please

i answered it ...

liberated heat=100 x 4.18 x (21.3-18.2)=1295.8 j =1.2958 kj
but the answer of the book was ..1295.8 kj
so i don't know the right answer

thanks
 
Last edited:


123 cBTU.
 


i m sorry ..i didn't understand your answer ..
 


You have edited your post while I was composing mine, I have not seen your answer.

1298 Joules or 1.298 kJ it is (assuming data you have listed is correct). 1298 kJ is wrong.
 

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