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Chemistry gcse reactions question - help!

Hi, I was doing this question in a paper (https://imgur.com/s7LtzL6a this is a picture of it), and the markscheme says it is an endothermic reaction because, I quote, "it takes in thermal energy/heat (from the surroundings)/as shown by the decrease in temperature (of the reaction mixture)"

I'm really confused as I thought that would make this reaction exothermic, due to the decrease in temp of the solution?

PS: Sorry if this is in the wrong spot, I'm new to TSR and don't know where to put this
(edited 3 weeks ago)
Think of it this way. An endothermic reaction feels cold as it is sucking heat out of your hand and consuming it. The reaction profile end up higher than it started as energy cannot be destroyed or created so it must have got it from somewhere - in this case the suroundings. Does that help?

Remember exothermic means exo "outside" thermic "heat" so gives heat to the outside world so it feels hot. endo thermic is the opposite "inside" "heat" so it sucks heat into itself.
(edited 3 weeks ago)
Reply 2
Original post by Hodders68
Think of it this way. An endothermic reaction feels cold as it is sucking heat out of your hand and consuming it. The reaction profile end up higher than it started as energy cannot be destroyed or created so it must have got it from somewhere - in this case the suroundings. Does that help?
Remember exothermic means exo "outside" thermic "heat" so gives heat to the outside world so it feels hot. endo thermic is the opposite "inside" "heat" so it sucks heat into itself.

Thank you for your reply, I'm getting there in terms of the explanation - but when you say that the endo reactions feels cold, does that refer to the reactants or the surroundings? I'm just a little confused since the answer to the question, when applying your answer to it, should be exothermic (as far as I know).

It could be a mistake in the mark scheme, since this is a sample assessment paper.
Feeling cold can be thought of as heat leaving your hand (or the surroundings) and going into the reactants. The surroundings "lose" thermal energy and the reactants gain it. That is why the reaction profile graph ends up higher than it started as there is more energy contained inside (remember "endo" means inside) the reaction.

It might be easier to think of an endothermic reaction as the opposite of an exothermic one. Exothermic reactions lose heat energy to the surroundings and the reaction profile ends up lower as there is less energy contained in the reaction.

The key to understanding is to do practice questions (the imgur link isn't working for me) and find different sources that explain it - one of them will make sense. Good luck and keep at it.

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