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What do you think will come up in Chemistry 32? :)

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And what about the ques in which the student weighed a differnt metal carbonate
we had to show some calculations...
 
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I used E=mct using the both temperatures the student got and another one with the mean temperature, and explained that it's justified because the result is more accurate as it is an average of the two heat changes (and also the enthalpy change would be an average)
 
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the reaction was NEUTRALISATION!! we have a similar question october november 2011 ppr 21 u can refer that ............... i think -ve sign is correct!!
 
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I used E=mct using the both temperatures the student got and another one with the mean temperature, and explained that it's justified because the result is more accurate as it is an average of the two heat changes (and also the enthalpy change would be an average)
i wrote something similar
 
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I got a negative value, but my original answers for enthalpy change were either way very low :/ 0.0103 KJ and 0.0490 KJ :/ My temperature change wasn't big
 
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i got -52.9 ..or somewhere around that
the values will be different for sure thats obvious caz the temperature n all varies everywhere.........ummm but i hope the final sign negative is correct am not sure about the value .......
 
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You can
check on Wikipedia it's aroun 900-1000 kj and it's positive not negative

the values will be different for sure thats obvious caz the temperature n all varies everywhere.........ummm but i hope the final sign negative is correct am not sure about the value .......

Well, for one thing, I am pretty sure the final answer was negative not positive. Thermal decomposition is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. Which means that the reaction of Na2CO3 from NaHCO3 is endothermic, meaning that the reverse reaction will be exothermic..
If you recall the reaction from our paper 32, it was 'Na2CO3 + CO2 + H2O = 2NaHCO3' yes? correct me if I am wrong. And we had to make this hess's law thingy which equated 3 reactions.nbnh.GIF
The question we got was in reverse but exactly the same!
 
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Well, for one thing, I am pretty sure the final answer was negative not positive. Thermal decomposition is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. Which means that the reaction of Na2CO3 from NaHCO3 is endothermic, meaning that the reverse reaction will be exothermic..
If you recall the reaction from our paper 32, it was 'Na2CO3 + CO2 + H2O = 2NaHCO3' yes? correct me if I am wrong. And we had to make this hess's law thingy which equated 3 reactions.View attachment 27422
The question we got was in reverse but exactly the same!
hmmmmmmmmmm....alhumdulilah!!!! the sign part freaked me out caz in my batch there was nobody who got NEGATIVE!!! yeayyy!!!!:)
 
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Well, for one thing, I am pretty sure the final answer was negative not positive. Thermal decomposition is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. Which means that the reaction of Na2CO3 from NaHCO3 is endothermic, meaning that the reverse reaction will be exothermic..
If you recall the reaction from our paper 32, it was 'Na2CO3 + CO2 + H2O = 2NaHCO3' yes? correct me if I am wrong. And we had to make this hess's law thingy which equated 3 reactions.View attachment 27422
The question we got was in reverse but exactly the same!
Oh wow thank god! You just saved me a week long of regret my friend haha I thought it was the enthalpy of FORMATION xD that's why I found such a high value on wikipedia D: many thanks :)
 
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