Question 1131078
A=Aoe^(kt)
0.47=0.50e(k*0.5), using hours as units
0.94=e^0.5k
ln both sides
-0.0619=0.5k
k=-0.1238

for 0.10 M
0.10=0.50e^(-0.1238*t)
0.2=e^(-0.1238t)
-1.61=-0.1238t
t=13.00 hours