How to calculate the cocentration of NHO3( nitric acid)
How to calculate the concentration of any compound , mixture or any élément? Which formula to use for ?

Concentration of substances is measured in mol/dm^3 (at least, in my country, I don't know if it's different in the other countries, but I'll stick to it.)

Ah, nitric acid is HNO3, I guess you made a slight mistake up there. For calculating concentration in my school problems, I do titration. Using the proper equation and reactants, I can find the concentration of nearly any substance, provided that I am given the concentration of the reactant I choose for the experiment.

For example, I have a 0.1mol/dm^3 aqueous solution of NaOH (sodium hydroxide). I titrate. Lets say that I used 25.0cm^3 of HNO3 to neutralise 25.0cm^3 of NaOH.

Using,

HNO3 + NaOH --> NaNO3 + H2O

I know that one mole of HNO3 will react with one mole of NaOH. By these values, I can easily find the concentration of the HNO3.

Hoped it helped. If you need more explanation, post and say where you can't understand very much.

concentration is calculated using this formula

n=cv
then you rearrange to get c
you need more info than just HNO3 to calaculate it

number of mol and volume
hope this equation helps

malb