q=mcdeltaT A2 question

So i was doing a past paper unit 5 aqa jun 13 and a Q=mcdeltaT question completely threw me off

"A solution is formed when 5.00 g of potassium chloride are dissolved in 20.0 g of water.The initial temperature of the water is 298 K.Calculate the final temperature of the solution.In your calculation, assume that only the 20.0 g of water changes in temperature andthat the specific heat capacity of water is 4.18 J K^–1 g^–1"

It was also previously given in the Q stem that the detaH solution of KCL is 17.2

to obtain the corrrect answer, it was necessary to realise that the "heat absorbed" i.e. 'q' in q=mcdeltaT, can be obtained by multiplying the deltaH solution of KCL by the number of moles of KCL (5/mr)

i competely and utterly do not understand why

any help much appreciated. thanks

Hi hi-zen-berg

I find it hard to answer these questions by typing so please see the attached picture. It is x by moles because it is a rearrangement of the equation charco pointed out above.

I hope this helps!

Alex

YOU COMPLETE AND UTTER LEGEND!
this reallly really helped me visualize the Q and honed in on what i didn't get

thank you so, so much ajsullivan i hope you and your entire bloodline are forever blessed <3

Hi hi-zen-berg

I find it hard to answer these questions by typing so please see the attached picture. It is x by moles because it is a rearrangement of the equation charco pointed out above.

I hope this helps!

Alex