Got a question. Just did a indicative (practice) exam today and had a question about Qc.
No idea what Qc is, I know what Kc is, and the question followed after it (it was a part a,b,c type question). When I asked my friend about it after she pulled a face and said it could be chucked in the bin. Anybody able to explain what it is?
Cheers
Another question
From the same indicative exam I did there was a multiple choice question about structural isomers for the molecular formula: C4H11Cl
With the question asking how many structural isomers can be made from that formula. My question is how is it possible for a 4 carbon chain to have 11 hydrogens and a chlorine when a standard butane has 10 hydrogens?
The options for the question were:
A) 4
B) 6
C) 8
D) 10
Maddz
So Qc is the reaction quotient, it expresses the ratio of reactants to products at a given instant (so you would most likely be given the initial concentration of the reactants and products), however Kc (equilibrium constant) expresses the final concentrations at equilibrium for a reaction.
Both however are calculated using the same formula, Kc and Qc=[products]/[reactants]
What matters is the difference between the values of Qc and Kc.
If:
Qc=Kc the system is at equilibrium
Qc>Kc the system moves to the left or backward reaction
Qc<Kc the system moves to right or forward reaction
Hope this helps, 
All good, I'm sorry I have no idea of the second question, hopefully someone else will know
I have my chem feedback class this Monday, so I'm hoping something was a typo. I will post again with a solution if nobody finds one.
Forgot to write an update on Monday, so here it is. About the mc question with the molecular formula my teacher said it was a mistake and was literally impossible, so we all got a free mark lol
That makes sense, also hooray for a free mark 
hey guys can someone please go over the reaction pathways
what specifically about pathways?
Like which pathways are we supposed to mainly know for exams.
Because obviously not all of them are there
I would guess just mainly reagents and how to draw molecules as they are converted (i.e primary hydroxy to carbonyl (carboxylic acid)
Some example questions:
A Hex-3-ene has a Br added, what is the IUPAC name for it?
State the reagent(s) required to convert hex-3-ene to hexan-3-ol
If any specific I would predict how to go from the alkane/ene groups to hydroxy to carbonyl will be on there along with halos
Also, is it that the NHT are similar to the actual exam each year?
Sorry to bother everyone, but on the electrochemical series on the oxidant side of the reactions, there are two different water equations. Can someone tell me when to use these and why?
That is logical, and congratulations on the free mark.
Mod edited to remove spam link
Qc is the reaction quotient, used to determine if a reaction is at equilibrium (compared to Kc). It predicts if the reaction will proceed forward or reverse. Think of it like predicting your moves in the Slope Game - adjusting strategy to stay balanced. If Qc < Kc, the reaction moves forward; if Qc > Kc, it reverses. Keep practicing, and you'll master it!
