Horacio's question thread!!!!! plz

[MagicGecko]

CO2 is added to 1.00 L of pure water at 25°C in a pressurised bottle. The pressure of CO2 above the water was raised to 3.00 atm and the gaseous CO2 came to equilibrium with the CO2 dissolved in the water. At equilibrium, the mass of CO2 dissolved in the water was 5.00 g.

The equilibrium constantfor this reaction, in atm M^-1, can be written as
                  K= p(CO2,g)
                       ------------
                       [CO2(aq)]

where p(CO2) represents the pressure of CO2.
calculate the value of this equilibrium constant at 25°C

im not sure how i should start it off, i mean for intance what does the Kn mean? is that something to do with moles?
should i use pv=nrt if so when?

im not asking anyone to actually do this for me just a starting point. 

thank yu!

[Starlight]

Yeah I think you use pv=nrt first to find n

Do you have the right conversions? Use p= kilopascals, v= litres, r= 8.314 JK^-1mol^-1, t= kelvin

[MagicGecko]

Yeah I think you use pv=nrt first to find n

Do you have the right conversions? Use p= kilopascals, v= litres, r= 8.314 JK^-1mol^-1, t= kelvin

ohh! i think i get it!
thanks!!! hahaha turns out you werent meant to use PV=nRT  at all
i emailed the answer to my teacher and he said it was correct! thanks!

btw this was i did.

i found out the moles using the n=m/Mr rule
n(CO2) = 5.00/44 = 0.1136 mol

Since V = 1.00 L, [CO2] = 0.1136 M *
Kn = p(CO2) / [CO2(aq)]
= 3.00 / 0.1136
= 26.4 *

hahaha

[Starlight]

Yeah I think you use pv=nrt first to find n

Do you have the right conversions? Use p= kilopascals, v= litres, r= 8.314 JK^-1mol^-1, t= kelvin

ohh! i think i get it!
thanks!!! hahaha turns out you werent meant to use PV=nRT  at all
i emailed the answer to my teacher and he said it was correct! thanks!

btw this was i did.

i found out the moles using the n=m/Mr rule
n(CO2) = 5.00/44 = 0.1136 mol

Since V = 1.00 L, [CO2] = 0.1136 M *
Kn = p(CO2) / [CO2(aq)]
= 3.00 / 0.1136
= 26.4 *

hahaha

oh right haha woops, it just seemed like it was heading in that direction with all the values given