I AM NOT SURE IF THIS IS CHEMISTRY BUT I NEED HELP ASAP I WILL GIVE BRANLIEST TO THE FIRST RIGHT ANSWER NO BOTS ALSO U WILL GET 50 POINTS

Calculate the number of molecules present in 0.750 mol of mgo.

Consider the reaction of a(g) + b(g) + c(g) => d(g) for which the following data were obtained: experiment initial [a], mol/l initial [b], mol/l initial [c], mol/l initial rate, mol/l. s 1 0.0500 0.0500 0.0100 6.25 x 10^-3 2 0.100 0.0500 0.0100 2.50 x 10^-2 3 0.100 0.100 0.0100 1.00 x 10^-1 4 0.0500 0.0500 0.0200 6.25 x 10^-3 what is the rate law for the reaction?

How many moles is 14.5 cm^3 of platinum? the density of platinum is 21.45 g/cm^3.