Chemistry help!?
1 mole of A and 2 moles of B were placed in a 1L reaction vessel. Calculate K if the equilibrium concentration of A was found to be 0.5M.
Please show work! 🙂
Favorite Answer
If you have 1 mole of A and 2 moles of B, those will react to form some amount of C. The coefficients of the balanced equation tell us that if you use up x amount of A, you will use up a corresponding 2x amount of B since you need twice as much B for the reaction. And you will make 2x amount of C since you get 2 moles of C for every one mole of A you use up.
So since you know that you have 0.5 M A at equilibrium (and the volume is 1L, so you have 0.5 moles of A), you know how much A you used up and you can use the variables above to therefore know how much B is left and how much C was made.
The K equation for a reaction in equilibrium is K = [C]^2/([A]*[B]^2) since the coefficients in the balanced equation turn into powers in the K equation. By now you’ve calculated the equilibrium concentrations of A, B, and C, so plug those into your K equation to get the value of K.
