What to use when equations require mass but given a volume ?

[CannonSLX]

In some questions, I've noticed that some questions which relate to equations that involve mass (Kg) and I am given a volume.

e.g
http://gyazo.com/169d40e27c5a14508724cb574635aca8

Know I that Δu=mCΔT, and I know that Δu=400w x t = m x 4200 x 60
and solve for t, but do I assumption that 1Kg = 1 L ?

 

[rock.freak667]

You were given the volume of 1 L and a density of 1 g/cm³.

What's the definition of density?

 

[CannonSLX]

You were given the volume of 1 L and a density of 1 g/cm³.

What's the definition of density?

Mass = Density x Volume

So would I convert the density to kg/m³ which is basically x1000 ?
and so the volume is 0.001m³

 

[rock.freak667]

Yes that's correct.

So you multiply the two and you get your mass in kg.

 

[CannonSLX]

Yes that's correct.

So you multiply the two and you get your mass in kg.

Have I done the question correctly ? (ignoring units) Mass = 1kg
400xt=1x4200x60

So the time is 630 seconds ?

 

[rock.freak667]

Yes that should be correct.