AQA Physics PHYA5 - 28th June 2016 [Exam Discussion Thread]

me (y)

Unfortunately

For 3ii https://089204f2d4bdbe672bf2453c0501f6d6b988ca38.googledrive.com/host/0B1ZiqBksUHNYLU1hNjFqdDRBb2s/June%202013%20MS%20-%20Unit%205-2B%20AQA%20Physics.pdf is my method not acceptable?

I done heat gained by ice= heat lost by glass and cola
= 0.25(840)(8.41-3) + 0.2(4190)(8.41-3)
=5669.68
Then I divided it by the latent heat of fusion of ice to get 0.01697....? Is this fine? Their way is completely different and I didn't use the heat capacity of water at all

Help!

@Protoxylic

Where does the bold bit come from?

Edit: I see what you've done.

You haven't quite equated the thermal energy change correctly. The thermal energy change of the ice will be equal to it's latent heat plus the thermal heat in raising its temp to 3 degrees

So because the beaker and the ice cooled to 3c, we need to assume the ice is now water at 3c?

Yeah they mean that the lowest temperature it got to was 3 degrees (ignoring the surroundings) which is when the whole liquid mixture gets to thermal equilibrium. So yes, the water that was ice, is now liquid water at 3 degrees at that point.

I'm dreading this exam but I'm so looking forward to ending this stupid thing called A level

Guys does anyone have a list of the formulas we need to know that aren't on the data sheet?

Off the top of my head the only one that isn't on there is P1 * V1 / T1 = P2 * V2 / T2

That can be worked out from the ideal gas law anyway can't it?