Chemistry
posted by D.Walker .
A zeroorder reaction has a constant rate of 3.20×10^−4 M/s. If after 35.0 seconds the concentration has dropped to 9.00×10^2M , what was the initial concentration?

[A] = [A]^{o}  kt
solve for [A]^{o}. You have k, t, and [A]. 
9.00 x 10^2= (3.20 x 10^4)(35)+A
9.00 x 10^2= (.0112)+A
9.00 x 10^2+.0112=A
A= .1012