Question

What is the mass if the density = 6.0 g/mL and the volume = 18 mL?

Answer 1

The equation for density is `rho=m/V`
Where `rho`=density, `m=mass` and `V`=volume

Explanation:

Fill in what you know:
`(6.0g)/(mL)=("mass " g)/(18 mL)`

Multiply both sides by `18mL` to get rid of the fraction:
`(6.0g)/(mL)*18mL=("mass " g)/(18 mL)*18mL`

`(6.0g)/(cancel(mL))*18cancel(mL)=("mass " g)/(cancel(18 mL))*cancel(18mL)`

`->"mass "=(6.0*18)g=108g`

Of course you could have done this faster by first reworking the equation into:
`m=rho*V` but that is not evident to everybody.