Answer to Question #144379 in General Chemistry for Katie

Question

You are determining the density of an unknown solid. You figure out the volume by water displacement. Then you weigh the solid, but forget to dry it off first. The calculated density will be larger, smaller, or the correct value? Why?

Answer 1

Q144379

You are determining the density of an unknown solid. You figure out the volume by water displacement. Then you weigh the solid, but forget to dry it off first. The calculated density will be larger, smaller, or the correct value? Why?

Solution :

The calculated density will be larger than the correct value.

Explanation :

If the solid is not dried properly or if we forget to dry it off before weighing, then the measured mass of the solid will be a little bit larger than the actual mass of the solid.

The formula of density is,

$$Density = {mass \over volume};$$

Here mass is present in the numerator ( top ). So if the measured mass is larger, then the calculated density will be larger than the actual density ( correct value).  

So we must dry the solid properly before measuring its mass.