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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Raaaaa on July 01, 2022, 06:36:49 PM

Title: Hess's calcuations
Post by: Raaaaa on July 01, 2022, 06:36:49 PM

(https://photos.app.no_way/m3qXAZeMkTqY2w999)

I can't even pretend I have the faintest idea how to do this. Any help? See image below

Thanks in advance

Title: Re: Hess's calcuations
Post by: Borek on July 02, 2022, 03:07:26 AM

What does Hess' law say?

Note: please read the forum rules (https://www.chemicalforums.com/index.php?topic=65859.0). You have to show your attempts at answering the question/solving the problem to receive help, it is a forum policy. Stating "I have no idea" doesn't count as an attempt, you can always google for the law involved and for example problems.

Title: Re: Hess's calcuations
Post by: Aldebaran on July 02, 2022, 04:45:16 AM

Hess's law is pretty straightforward but if you really have no idea where to start I suggest any high school text book or the following linked website as a good place to start. By the way, the website is a great resource for many other high school chemistry topics. It is well researched and written in a teach yourself style. Study the page and you should have no trouble solving the problem you posted but do come back if you get stuck having given it a go by yourself. https://www.chemguide.co.uk/physical/energetics/sums.html

Title: Re: Hess's calcuations
Post by: Orcio_87 on July 02, 2022, 03:20:55 PM

@Raaaaa - You have to add the reactions all together to calculate enthalpy of the one you want.