@taw1020 Thank you!
For #21, why would the answer not be C? If heat is a product, then increasing the heat would be like increasing the amount of product, which would shift the reaction towards the reactants and cause Kc to decrease, because Kc = products/reactants (this is my reasoning, at least, but clearly it’s not right).
taw this is my approach, please tell me if this is correct for 22
i used a rice table,
co+2h2----.ch30h
1 1 0
-x -2x +x
1-x 1-2x +x
so this means that whatever the initial concentration is, h2 would lose more than co, i think this is what you’re saying is it?
@apchemsos I’m not sure how to do the whole thing but I think you can definitely eliminate B) H+ because adding OH would never increase H concentration.
Would this happen maybe?
HClO2+OH- --> ClO2-+H2O making the answer C? I’m not sure but maybe that’s a possibility.
@Mathman97
Yeah, that’s the general thing I was trying to describe.
@sleepdeprived4
is this for 2014? my answer key says that it is C
Can anyone explain 56 on 2013?
for #29, is k1 not the dissolution equation? why do we have to mess with k3?
Also is you guys 2014 test 50 or 60 questions?
50
Did anyone else feel that the 2013 test was A LOT easier than the 2014 multiple choice?
@stemscholar Yeah, I think that makes sense. Thanks!
@taw1020 Oops, my bad, I was looking at the wrong answer on my answer key. No wonder I couldn’t figure out why it was wrong, haha.
lol the correct answer for 34 says as H+ is consumed, it becomes less acidic so ph increases? what??
Can somebody tell me if we have 105 minutes on the FRQ now? Or is it still 90?
105
105^
Does anyone know the rough estimate on how many MC questions you need to get write (out of 50) to get a 5 on the 2014 test? I can probably get around 2/3 of the FRQ points.
Why is density proportional to the product of molar mass and pressure (at constant temperature)?
Can someone please re-explain the 0.2 Faraday and mass of Zn produced? I don’t understand how you get 6.54grams from 0.1mol of Zn.
@APScholar18
The following reactions occurs:
(1) AgNO3 + MgCl2 -> AgCl + Mg(NO3)2
(2) Ag + Cl- -> AgCl
From Beaker Z, you can see that there are no excess Ag+ or Cl- ions. The amount of Cl- must equal the amount of Ag+. Therefore, in the original beakers, AgNO3 should have twice the concentration of MgCl2 (2 mol Ag = 2 mol Cl)
Eliminate A and B.
So from this, you now know that 2 mol of NO3- exist and 1 mol Mg+ exists. Mg+ and NO3- are 1:2 in magnesium nitrate, so the moles of Mg(NO3)2 is 1 mol. 1 mol / 2 L = .5M
So the answer is D
@Martin18
The molecular weight of Zn is 65.4 grams/mole, so .1 mol should be 6.54g? It just simple stoich.
@glasshours
It’s just rearranging the Ideal Gas Law.
PV=nRT
n/V = P/(RT)
let M = molecular weight
(Mn)/V = P/(RT)
Any guesses as to the cutoff for the raw score for a 5? I know it depends on the difficulty of the exam but… 