Calculation Question (1 Viewer)

[EpikHigh]

A student did an experiment to determine the molar heat of combustion of 1-propanol.
The following results were obtained
Mass of 1-propanol burnt - 0.60g
Mass of water heated = 200g
Initial Temp of water = 21.0C

The molar heat of combustion of 1-propanol is 2021kJ mol-1. Assuming no heat loss, what would be the final temperature of the water?

Can't seem to be getting the right answer, can someone give me worked solution to this please.

 

[girlworld_club]

will do.

Ok so you have 0.60 g propanal used so that is 0.60/60 moles = o.o1 moles
So 0.01 moles releses x amount of energy, we know 2021kj is relesed by 1 mole, so we do a ratio and solve
so we do 0.01 x 2021 which is = 20.21 kj
since q is mesured in joules we convert to j so it is now 20210J

Now we sub to find temperature change
20210 = 200 x 4.18 x change in temp

when you find change in temp, simply add it to initial temp which is 21.

Hope this helps, this is how i solve these questions

 

[EpikHigh]

will do.

Ok so you have 0.60 g propanal used so that is 0.60/60 moles = o.o1 moles
So 0.01 moles releses x amount of energy, we know 2021kj is relesed by 1 mole, so we do a ratio and solve
so we do 0.01 x 2021 which is = 20.21 kj
since q is mesured in joules we convert to j so it is now 20210J

Now we sub to find temperature change
20210 = 200 x 4.18 x change in temp

when you find change in temp, simply add it to initial temp which is 21.

Hope this helps, this is how i solve these questions

Thanks! I made a stupid mistake, I forgot to convert the 20.21Kj back into joules I just left it as kj and I was like wtf. Thanks again for solving