Given the following equation:

SO2 + NO2 <--> SO3 + NO

At 25 Celcius, 2.00 mol of each of SO2 and NO2 are introduced into a 1.0L sealed flask. When euilibrium is reached, it is found that
[NO2] = 1.30 mol/L
[SO3] = 1.30 mol/L

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Calculate the concentration at equilibrium of SO2 and NO2.

detailed answer, please, and thank you.

and Calculate the K value at 25 degrees Celcius

If 1.3 moles of each reactant is used, then 2 minus that is how much remains.

concentration = amount left/volume