math for laboratory science
posted by mikela .
Determine the quantity of stock 75.0% v/v EtOH required to prepare 300ml of a 25.0% v/v EtOH solution

quantity here refers to the volume you need to extract from the 75% ethanol to make 25% ethanol in 300ml.
i would use a dilution equation c1v1=c2v2 and find v2 such that;
v1=(c2/v2)/c1 where c1 is 75%, c2 is 25%, v2 is 300ml.
hope that helps