<span><span>There is no formula. The speed of light is a fundamental constant which appears in other formulas but there’s no formula to compute the numerical value.Well, actually, that’s not quite right. The numerical value in meters per second is known exactly, because we use the speed of light to define the meter. It is: <span><span><span>c=299,792,458 m/s</span><span>c=299,792,458 m/s</span></span>
</span>. Exactly. But the thing is — this value is purely an artifact of our unit system. Other unit systems will give other values, so the number value is entirely arbitrary.</span></span>
OC. (Third one) is balanced
<u>Answer:</u> The correct net ionic equation for the reaction is 
<u>Explanation:</u>
Net ionic equation is defined as the equations in which spectator ions are not included.
Spectator ions are the ones that are present equally on the reactant and product sides. They do not participate in the reaction.
The balanced molecular equation is:

The complete ionic equation follows:

As calcium and sulfate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:

Hence, the correct net ionic equation for the reaction is 
It can form a covalent bond with a hydrogen bond that has one valence electron to have eight valence electrons and become stable.