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KC values?

I'm trying to do my homework and i've tried every logical way I can think of for this question, can anyone help?

The equilibrium constant for A --> B is 39 when at 100 degrees C. If you had 2.00 moles of A at the start, how much would be left at equilibrium at this temperature?

Thanks for any help, much appreciated!

Reply 1

charco

Study Forum Helper

Original post by thegaypixie

let moles of A reacted at equilibrium equal x ...

Reply 2

thegaypixie

Original post by charco

let moles of A reacted at equilibrium equal x ...

Thanks

Could you help me on the last question as well?

Reply 3

charco

Study Forum Helper

Original post by thegaypixie

Thanks

Could you help me on the last question as well?

Which last question? There was only one!

Reply 4

medhelp

Original post by charco

let moles of A reacted at equilibrium equal x ...

isnt kc calculated using concentration values tho
like how do we work that out if kc = conc products / conc reactants
we only have mol here?

Reply 5

Metanoia

Original post by medhelp

isnt kc calculated using concentration values tho
like how do we work that out if kc = conc products / conc reactants
we only have mol here?

For this question, the volume "does not matter" as the sum of the Stoichiometric coefficients are the same on both sides of the equation.

Let the volume be an unknown 'V' when we write out the respective concentrations, the 'V's will cancel each other out when substituted into the Kc expression.