Help on conversion with mass involved

rt3ll3z

1. The problem statement, all variables and given/known data

Grains of fine California beach sand are approximately spheres with an average radius of 45 µm and are made of silicon dioxide. A solid cube of silicon dioxide with a volume of 1.00 m3 has a mass of 2600 kg. What mass of sand grains would have a total surface area (the total area of all the individual spheres) equal to the surface area of a cube 1.50 m on an edge?

answer is in kg
2. Relevant equations
volume of sphere=4/3*pi*r^3


3. The attempt at a solution

rock.freak667

So what is the volume of 1 grain of sand?

What is the density of the Silicon dioxide?

What is the surface area of 1 sphere?