Related questions

Question

Hi, In this question I understand that we should test and see if x will be negligible or not and in order to do that, we can take the initial concentration/value of kc to see if it’s bigger or smaller than 500, if the no. is bigger than 500, then we’ll ignore the x, if it’s smaller than 500 then we’ll do quadratic formula. Am I right? I’m honestly confused because I don’t understand when to use the “100 rule” or the “5%” rule? What's the difference between these