How many grams of sucrose would you dissolve in water for a total volume of 500mL to make a 5% solution?
5 percent by weight? When you cite percent in solutions, historically pharmacists have messed up our thinking.
5% can be 5% weight/weight, weight/volume, or volume/volume.
(pharmacists make no distinction on weight or mass, duh)
Yes, confusing, but you have to specify.