The amount of substance after t hours with the given half-life can be calculated through the equation,
A(t) = A(o) x (0.5)^(t/h)
where A(t) is the amount after t hours, A(o) is the original amount, h is the half-life.
Substituting the known values from the given,
It must be noted that the number of minutes should be converted first to hours by dividing it by 60.
A(t) = (344 g) x (0.5)^((538/60)/26))
A(t) = 270.86 g
Thus, the amount of as-76 after 538 minutes is approximately 270.86 g.
