Answer Happy

HI!! Please explain each step on how to get the answer on a
Casio calculator. Thank you.
liquid aspirin preparation which is 325mg/mL. The solubility of
aspirin at 25ºC is 0.33g/100ml. This tells us that we
have a suspension. We have a suspension so its
degradation follows zero order kinetics.
k0 is zero order rate constant,
k is the first order rate constant for the portion of drug in
solution.
Cs is the concentration of a saturated solution of the drug in
the suspension
C0 is the starting potency of
suspension
its degradation follows first order
kinetic. We know that, at room temperature, aspirin
in solution degrades at 10% in 6.5hr. So we can calculate the first
order rate constant for decomposition of aspirin in SOLUTION
Then we need to calculate the zero
order constant ko:
Ko=k×Cs
Ko=0.016 x 0.33g/100mL (watch units
match!!!!)
Ko=5.28 x 10-3 g/100mL/hr
Having calculated the zero order rate constant ko, we
now use the equation:
Note units for ko are g/100mL/hr, so we need C
in terms of g/100mL
Co= 325mg/5mL= 6.5g/100mL, and 90% of
C=5.85g/100mL
5.85=6.5- 5.28 x 10-3 x t
t= 123 hours
first order rate constant A=A.e-kt zero rate order constant: ko=kCs then use zero order equation A=A.-kot