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Thermochemistry questions(1)

Posted: Tue Jun 29, 2021 10:18 pm
by Dhamnekar Winod
A 48.59 gram sample of iron (with a heat capacity of 0.450 J/g ºC) is heated to 100.0 ºC. It is then transferred to a coffee cup calorimeter containing 66.51 g of water (specific heat of 4.184 J/ g ºC) initially at 20.63 ºC. If the final temperature of the system is 23.59 ºC, how much heat was absorbed by the calorimeter? Record your answer as a whole number (assume the sign is positive).

I am working on this question. Any chemistry help, hint or correct answer will be accepted.

Re: Thermochemistry questions(1)

Posted: Tue Jun 29, 2021 10:44 pm
by ChenBeier
It is not asked. You can calculate the heat what was absorbed by the water.
But you could calculate the Initial temperature of iron.

Re: Thermochemistry questions(1)

Posted: Wed Jun 30, 2021 10:49 pm
by Dhamnekar Winod
This reaction released 1670.743 J of heat out of which 847.04 Jwas absorbed by coffee-cup calorimeter and 823.70 J was absorbed by water.

Re: Thermochemistry questions(1)

Posted: Thu Jul 01, 2021 12:43 am
by ChenBeier
The absorbtion of 823,7 kJ/ mol for water is correct. But how you get the other values. What is the 7nitial temperature of iron?

Re: Thermochemistry questions(1)

Posted: Thu Jul 01, 2021 3:11 am
by Dhamnekar Winod
Initial temperature of iron was 100.0℃ and its final temperature is equal to final temperature of the system which is 23.59℃. So ∆T for 48.59 g sample of iron is 100.0℃- 23.59℃= 76.41℃.
If you read carefully, you will notice that the questioner asked how much heat absorbed by coffee cup calorimeter, not by water.

Re: Thermochemistry questions(1)

Posted: Thu Jul 01, 2021 9:47 am
by Orcio_Dojek
True, but calorimeter constant is unknown.