Gas laws problem (need quick help )

[mjolnir80]

gas laws problem (need quick help please)

Homework Statement

ill try to describe the situation as best i can
at first we have a flask (150 ml) with 0.1g of NaHCO₃ we attach a syringe with 20ml of acetic acid (CH₃COOH ) to it (and seal it off so nothing escapes)
we inject the acetic acid into the flask and pull the syringe back (so the overall volume doesn't change) the 2 compounds react and produce CO2
the initial(before adding the acetic acid) temp. = 295.6k
initial pressure = 1.020 atm
final temp. = 297.6 k
final pressure = 1.176
what is the initial amount of gas in the flask(in mol)?
and what is the amount of CO2 added(in mols)?
what is the partial pressure of CO2

Homework Equations

ideal gas law equations

The Attempt at a Solution

i used pv=nrt to calculate the initial amount of gas (using the initial conditions) = 6.45*10^-3 mol
for the second part i use PV/nT(initial)=PV/nT(final) to get the amount of mols after the reaction but i get a value less than the first one. this doesn't make sense since we are adding gas to it (note that this was a real experiment and the values might be off from an ideal situation)
can someone help me out with this and maybe hint at what to do on the last 2 parts ?

i really appreciate the help

 

[Borek]

Use PV=nRT for he second part as well. PV/nT=const holds only for constant n.