The density of ice is 920 kg/m3 and that of sea water is 1030 kg/m3 . what fraction of the total volume of an iceberg is exposed? show your work, don't just state the answer.

To be floating, the gravity force of the iceberg should be same as the buoyancy force that result from the difference of the ice and water density.
The density of ice is 920 and water is 1030, then the difference should be: 1030kg/m3-920kg/m3= 110kg/m3

Let say that the volume of ice below the water is volume1 and the volume above the water(exposed volume) is volume2.
You can get this equation

volume1+volume2= 100%
volume1= 100%- volume2

Insert it into the buoyancy and gravity force will result
buoyancy=gravity
110kg/m3*volume1= 920kg/m3 *volume2
110kg/m3*(100%- volume2)= 920kg/m3 *volume2
110kg/m3 - 110kg/m3*volume2= 920kg/m3 *volume2
110kg/m3 = 1030kg/m3 *volume2
volume2= 110/1030= 0.1067= 10.7%

Enzyme make a hormone as a catalyst

Ithink this is what you meant. the temperature at which a liquid begins to boil is called the boiling point. the boiling point of water is 212°f or 100°c.  and at that point will start to turn into steam (gas)