The chemist the count the number of particles (Atoms, Molecules or Formula Unit) in a given number of moles of a substance by using following relationship.
Moles = # of Particles / 6.022 × 10²³
Or,
# of Particles = Moles × 6.022 × 10²³
So, from above relation it is found that 1 mole of any substance contains exactly 6.022 × 10²³ particles. Greater the number of moles greater will be the number of particles.
<u>Answer:</u>
<u>For a:</u> The balanced equation is 
<u>For c:</u> The balanced equation is 
<u>Explanation:</u>
A balanced chemical equation is one where all the individual atoms are equal on both sides of the reaction. It follows the law of conservation of mass.
The given unbalanced equation follows:

To balance the equation, we must balance the atoms by adding 2 infront of both
and
and 3 in front of 
For the balanced chemical equation:

The given balanced equation follows:

The given equation is already balanced.
The given unbalanced equation follows:

To balance the equation, we must balance the atoms by adding 2 infront of 
For the balanced chemical equation:
The given balanced equation follows:

The given equation is already balanced.
Chemical bonds is the answer