How does physical properties differ from chemical properties?

a.) physical properties can be observed and chemical properties cannot.
b.) physical properties cannot be observed and chemical properties can.
c.) chemical properties are observed using your senses.
d.) chemical properties can only be observed using your taste sense.

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.

3) in peaches, [oh]=3.16x10-11 m a) find [h+ ] b) what is the ph? c) is the solution acidic, basic, or neutral?

Which of the following is the correct formula for copper (i) sulfate trihydrate? cuso4 · 3h2o cuso4(h2o)3 cu2so4(h2o)3 cu2so4 · 3h2o