Finding the expected value in a Chi Square Test

I am examining two sets of third grade students (130 in each set) who took the state test. The first group attended a pre-k program and the second group did not. Do I use the E=np formula for finding the expected frequencies for passing the test, with n being 130 and p being 2?
130 = the total number of observations (total number of student in the group)
2 = the probability for each category (pass or fail)