[moni]

what is the minimum mass of CaCo3 required to establish equilibrium at a certain temp in 6.50 L container,if the equilibrium constant  Kp is 0.050 for the decomposition reaction of CaCO3 (s) <==>CaO (s) + CO2 (g).please help

[plu]

For a start, assuming that the temperature is 298 K (which is actually very unlikely for this particular reaction), calculate the number of moles of CO₂ you'll need to fill the container at the given pressure.

[moni]

that is why i have a problem ,i don't know the temp. ,i dont have the pressure.have no idea where to start

[Yggdrasil]

If they don't give the temperature or pressure, you can probably just assume its at room temperature (298K, 25C) and pressure (1 atm).  Just be sure to state your assumptions and you should be fine.

[Borek]

Alternatively, it may mean you are asked to derive a formula for mass needed in function of temperature.

[plu]

You can assume temperature is 298 K.  Pressure is given to you by the K_p expression.

[AWK]

Always start from writiing down an expression for Kp. Then you can notice Kp is equal to pressure of CO2 in atm. And finally you can calculate moles of CO2 for any assumed temperature (moles of CO2 are equal to minimal number of CaCO3 moles at this temperature)