An example of a base in chemistry would be like soap or lye
A cell is made of molecules and a molecule is made of atoms. That's the simplest way of putting it. More complicated is that a cell is made up of macromolecules, such as proteins, lipids, etc. A molecule is a particular configuration of atoms.
This is not easy. For many of the chemical elements there are several known isotopes. Isotopes are atoms with different atomic masses which have the same atomic number. The atoms of different isotopes are atoms of the same chemical element; they differ in the number of neutrons in the nucleus.
The following answers:
1. B
2. D
Answer: a) 49.8 gram
b) 47.0 %
Explanation:
First we have to calculate the moles of glucose
The balanced chemical reaction will be,
From the balanced reaction, we conclude that
As,1 mole of glucose produce = 2 moles of ethanol
So, 0.54 moles of glucose will produce = 
mole of ethanol
Now we have to calculate the mass of ethanol produced
Now we have to calculate the percent yield of ethanol
Therefore, the percent yield is 47.0 %
