Jorge has an unknown mineral. The mineral has a mass of 21 grams and has a volume of 3cm3. Calculate density and find his unknown material

7g/cm³

Explanation:

Given parameters:

Mass of the mineral  = 21g

Volume  = 3cm³

Unknown:

Density of the mineral  = ?

Solution:

Density of a substance is the mass per unit volume of the substance.

 Density  =  

  Now insert the given parameters and solve;

  Density  =   = 7g/cm³

The mineral with a density of 7g/cm³ is Galena, an ore of lead.

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)