Why might the percent yield of copper produced be less than 100% of the expected amount?

[ ] There are impurities in the substances.
[ ] The reaction might not have gone to completion.
[ ] The amount of one of the reactants might be measured incorrectly.

(you can pick multiple)

Motivation cannot be developed with practice; a person either possesses it or they do not.

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

Which are examples of how technology has advanced scientific understanding.1using hot water to sterilize medical equipment.2transplanting a human organ into another individual.3inserting genes from one sheep into another cell to make a cloneunderstanding the different structures that make up a cell.4examining microorganisms from the deepest parts of the ocean