The specific gravity of iron is 7.87, and the density of water at 4.00c is 1.00g/cm3. you can use this information to find the density of iron. find the volume occupied by 7.00g of iron

The specific gravity is the ratio of the substances density to that of water at 4 degrees Celsius. With this, it is conclusive that the density of iron is 7.87 g/cm³. The volume occupied by the iron is the quotient when mass is divided by density,
 
                           V = m / D  = (7 g) / (7.87 g/cm³) = 0.89 cm³

Therefore, 7 grams of iron occupies approximately 0.89 cm³. 

Let us first write down all the information's that are already given.
Specific gravity of iron = 7.87
Density of water at 4 degree centigrade = 1.00 g/cm^3
Mass of iron that is given in the question = 7.00 g
Now
Specific gravity of iron = Density of iron/density of water
So
Density of iron = specific gravity of iron * density of water
                        = 7.87 * 1 g/cm^3
                        = 7.87 g/cm^3
We also know
Volume = Mass/ Density
So
Volume of iron = 7/7.87 cm^3
                        = 0.89 cm^3
So the volume of 8.00 gm of iron is 0.89 cm^3. i hope the answer comes to your help.