Consider the reaction: H2(g) + I2(g) ⇌ 2 HI(g) A reaction mixture at equilibrium at 175 K contains PH2 = 0.958 atm, PI2 = 0.877 atm, and PHI = 0.020 atm. A second reaction mixture, also at 175 K, contains PH2 = PI2 = 0.621 atm and PHI = 0.101 atm. Is the second reac- tion at equilibrium? If not, what will be the partial pressure of HI when the reaction reaches equilibrium at 175 K?

Video transcript

Hello everyone in this problem. We want to identify the second reaction is at equilibrium. So how we do this is first solving for R K. P value. Then we go ahead and check the second container if it's an equilibrium. To see if the value of the Q will equal to the value of R K P. So our equilibrium expression 1st is that K. P. Is equal to the concentration of R N Squared divided by the concentration of RN 204. So let's go ahead and actually highlight the equation that I'm using. And as you can see my starting materials is going to be on the denominator here and my product is N 20. Why I have this two here is because we have two moles of the N 20. Alright, let's go ahead and calculate for K. P. Then. So K P is equal to. So basically we're using this here and we're putting in the numerical values from the given and the problem. So we have the concentration of N20. Being 0.0607. Of course. To the second power divided by the pressure of the N 204 which is at 0.512. So put everything into my calculator. I'll get the value for my K. P. being 7.20 times 10 to the negative third power. So the next step is to calculate for our Q value and it should match with this K. P value exactly right? Let's go ahead and do that then. So my Q value is equal to The pressure of 0.0342 to the second power. So this is just the information given to us from our second container divided by the concentration of the pressure of our starting material. So 0.163. Now putting that into my calculator, I get my Q. Value being 7.20 times 10 to negative three. So our key value again is 7.20 times 10 to the negative three is indeed equal to R. Q. Value of 7.20 times 10 to the negative three. This is my Q. This is my K. P. They equal each other and that means we are in equilibrium. So I would say Q. Equals K. P. Which means de delivery. Alright. And this is going to be my final answer for this problem. Thank you all so much for watching.