Standard solutions : I'm confused Watch
You then weigh the weighing bottle and subtract the mass of the bottle from the mass of the bottle and the solid together to get the precise mass of the solid you weighed out.
My question is, wouldn't this mass be less than the one you wanted to measure out? Is there an error in the book?
It doesn't matter if the precise mass of solute used is slightly less than desired, you can calculate the exact concentration of the solution using the precise value. This is fine in a school practical but in industry obviously a more accurate mass would be needed.