<PRE><B>Question 883641</B>
ASSUMPTION:  You meant 8 fluid ounces, a measure of volume.


You (potentially) need to know the density of your liquid.

1 fl. oz.  = 28.413 ml.  (approximation).


You may want to view your percent concentration as % mass per volume, typically stated as % w/v.  This way, and for such a very dilute powder concentration, you do not need density.


{{{8(flOz)*28.413(ml/flOz)=VolumeOfLiquidInMILILITERS}}}


Amount of your powder to add, g grams of powder to add:
{{{highlight(g/(8*28.413)=0.2/100)}}};
Solve for g.</PRE>