What is the mass of 4.84 x 1024 molecules of C3H8?

Does anyone know a lot about how to: - calculate mass of magnesium metal - calculate the actual yield of magnesium oxide - calculate the theoretical yield of mgo - calculate the percent yield of mgo - determine the percent yield of mgo - determine the average percent yield of mgo i had to do an online lab and its asking these questions but i have no idea where to start or how to be able to find these things. i can post the chart of the data from the lab or if you can tell me exactly how i can find each.

What is the amount of energy for a photon that has a 125 cm wavelength

Which of the following isotopes has the same number of neutrons as phosphorus-31?