A
L = A
O(1/2)
t/n
AL is your remaining concentration, AO is your original concentration, t represents the time and n is the half life.
Now in this case, 0.52M will be your AO, the 'n' will be 2.36 hours and the time will be 752 seconds (dont forget to convert seconds into hours!!)
Now all you have to do is plug these numbers into your equation and solve for AL, which will be your concentration after 752 seconds. I hope this helps!!