Question

Can someone help me understand this problem and help me set it up.

Gaseous hydrogen bromide decomposes at elevated temperatures according to the following equation: 2HBr(g) yields H2(g) + Br2(g)
At a certain temperature a 2.00L flask is initially filled only with 0.600 mol of HBr What is the value of Kc at that temperature if the flask contains 0.104 mol of H2 at equilibrium?

Answer 1

write an equilibrium expression, make an I.C.E. table, plug the values into the expression.

Answer 2

Before making the ICE table is our Q the 2.00 since we are trying to find the Kc value? I don't know if my wording is correct

Answer 3

Q = cue?

Answer 4

lol

Answer 5

no i'm asking if "Q" meant "cue"?

Answer 6

You know how "Kc" is the equilibrium concentration "Q" is the reaction quotient

Answer 7

oh, in those terms. I didn't know what you meant by Q.

Kc is the equilibrium constant not concentration :P

Answer 8

yeah

Answer 9

So the setup of the equation is K=(H2)(Br)/(HBr)^2

Answer 10

yes

Answer 11

Where I am getting confuse is on the ICE table. I don't know where to put the 2L.. Is it on the CHANGE line under the 0.600 in HBr?

Answer 12

the 2L is scaling the amount of moles you have (to concentration), you're not incorporating it into the table directly.

Answer 13

ok. So I put together what I have: 0.104/0.600^2 give me 0.2888. I don't think that is the answer

Answer 14

you didn't use an ICE table though.

you have t find the values at equilibrium 0.6 moles is an initial conc.

Answer 15

And 0.104 is the other initial concentration for H2

Answer 16

I setup my ICE table but it's not making any sense

Answer 17

nope, "the flask contains 0.104 mol of H2 at equilibrium"

Answer 18

can you post it?

Answer 19

yes