Features that describe motion of an object

Iron reacts with sulfur to form iron sulfide. if 60 grams of iron reacts with sulfur to produce 90 grams of iron sulfide, how much sulfur has been used in the chemical reaction?

Curious carl calculated the density of a cube to be 4.50 g/cm3. what is the density of the cube in g/l?

Describe the function of the endomembrane system? what organelles are involved?