How to convert Gdm-3 to moldm-3

Since it is still in dm^-3 (which is basically a Litre)

You just need to convert the g into moles using the formula:

moles = mass/molar mass

= 5.6 / (39.1+16+1)

= 5.6/56.1

= 0.1 moles

So this makes it 0.1 moles dm^-3