The mass of a cube of iron is 277 g. Iron has a density of 7.87 g/cm3. What is the mass of a cube of lead that has the same dimensions?

Answer 1

After treating a coloured solution of a compound with activated charcoal, filtering and drying the product, the colour of the product was grey. What caused the grey colour? How can the grey colour be removed?

Answer 2

volume Fe = mass/density.
Solve for volume Fe.
mass Pb = volume x density Pb. The density of Pb is about 11.3 g/cc but you should confirm that.