Answer:

Explanation:
Percent yield is a ratio of the actual yield to the theoretical yield. It is found using this formula:

The actual yield is 12 liters, because that was actually produced in the lab.
The theoretical yield is 20 liters, because that was the expected yield.



For this reaction, the percent yield is 60%.
(does this belong in chemistry?)
anyways, the parent was most likely a kid who wanted privacy. they wanted something so they are giving it to their kids.
Carbon has 4 valence electrons, oxygen has 6
You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.