What is the best way to measure a reaction efficiency

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 must happen before a body cell can begin mitotic cell division

Acamcorder has a power rating of 17 watts. if the output voltage from its battery is 7 volts, what current does it use?units: