Given an reaction, how to find the ionic concentrations of each substance?

Answer 1

The concentrations formula:
M=n/V

Example:
What is the concentrations of H+ in 100ml HNO3 0.10 M?
Solution:
First, make the equation,
HNO3 --> H+ + NO3-
HNO3 mole = 100 * 0.10 = 1 mmole
H+ mole = 1 mmole
H+ concentration = 1 / 100 = 0.10 M

That's all
Hope it helps

peace
vixklen