Question

When finding the density of a liquid, why must you first find the mass of a graduated cylinder alone?

Answer 1

Let's start with `"density"`. How do we define it?

Explanation:

`"Density, "rho` `=` `"Mass"/"Volume"`.

Now clearly, when we make such a measurement, it is useful to measure a large mass, and a large volume simultaneously to make the measurement. So take a `100*mL` graduated flask, measure the tare, i.e. the empty mass `(i)`, and then fill it to volume, and then take the mass `(ii)` when full.

`(ii)-(i)` is the mass of the liquid, and thus, `rho=underbrace((ii)-(i))_"mass of liquid"/underbrace(100*mL)_"volume of liquid"` with units of `g*mL`, or equivalently `g*cm^-3`. Is this what you want?