Answer:
6.0221409e+23
Explanation:
The number of molecules in a mole of any substance is Avogadro's number, 6.0221409e+23.
An element is a substance made from only one type of atom (e.g. oxygen is an element made up of only oxygen atoms).
An atom is the simplest form of an element that can exist, such as a lithium atom (Li).
Atoms of different elements can be combined together to create compounds, e.g sodium oxide (Na2O).
A molecule is a combination of 2 or more atoms that form chemical bonds. When these atoms are of the same element, they can be called molecules (e.g. O3 - ozone).
However when a molecule is made up of atoms of different elements, they are classified as compounds (e.g. CO2 - carbon dioxide).
So all compounds are molecules, but not all molecules are compounds.
The reduction reaction is the gain of electrons while oxidation reaction is the loss of electrons. For potassium ion(K+), the reaction should be K+ + e- ==> K. So the answer is (1).