in tank with volume 5 L contains 0.176 mol of NO in 298k temperature, then we put in this tank 0.176 O2
so we got a reaction that create NO2.
I need to write the balanced equation for this reaction.
so this what I got but I sure is not correct. NO+O2--->NO2 ? How can I get NO2 from NO+O2?

thanks.

No, it's not balanced. Can't you see how to do it? Hint: you need to use the number "2". (Twice)

well yes I see that is uncorrect.
SO NO+1/2O2---->NO2 now is OK?

and I got second section that says: in tank with volume 5 L contains 0.176 mol of NO in 298k temperature, then we put in this tank 0.176 O2 in same temperature
I need to calculate the total pressure in the end of the reaction.
what mean I need to find P=PO2+PNO? If yes I use this formula PV=nRT for each gas yes?

thank you

You usually shouldn't use fractional coefficients in chemical equations. How do you fix that?
Since there are three gasses involved in the reaction, you have to determine which ones are present at the end. Then add the partial pressures as you show.

well I don't know how to fix the chemical equations more then I showed.
:)

To remove the fractions, multiply the coefficient of every molecule/atom by the denominator of the fraction. In your equation, you get:

2NO + O_2 \rightarrow 2NO_2

Assuming that all the oxygen reacts, you get a new total number of moles

You then have to get:

P = P_{NO_2} + P_{N_2}

or

P = P_{NO_2} + P_{O_2}

depending on the reagent in excess.

P for each is obtained from PV = nRT

where n is the number of moles of the molecules concerned.

Unknown008 is completely correct (as usual). Now you have the moles of reactants, and the correctly balanced equation so you can figure the quantities of all species present at the end.

Well, I'm not mistake-proof though :o

Thanks :)