For the dissociation of CaCO_3 at 25 degree C; CaCO_3 (s) CaO (s) + CO_2(g) Delt
ID: 987419 • Letter: F
Question
For the dissociation of CaCO_3 at 25 degree C; CaCO_3 (s) CaO (s) + CO_2(g) Delta G* = *131 kJ middot mol^-1 A sample of pure CaCO_3 (s) is placed in a flask and connected to an ultrahigh vacuum system capable of reducing the pressure to 10^-9 mmHg. Given that Substance Would CO_2 (g) produced by this reaction be detectable in the vacuum system at 25 degree C? Explain. What additional information would you need to determine P_CO2 as a function of temperature? With necessary data from the provided table (or the table in Appendix D from your textbook!), determine the minimum temperature to which CaCO_3(s) would have to be heated for CO_2 (g) to become detectable in the vacuum system.Explanation / Answer
(a) The pressure is 10-9 mm Hg which is too low and when pressure is too low, volume would be too high, CO2 formed can exapnd very easily and its concentration would be too low and might not be detectable in the vacuum system
(b) number of moles of CO2 and volume of CO2
(c) Assuming n = 1 mole
R = 0.0821 L-atm/mole*K
P = 10-9 mm Hg * 1 atm
1 760 mm Hg
= 1.315 * 10-12 atm
Lets say volume = 1 litre
PV = nRT
PV = T
nR
= (1.315 * 10-12 atm) * (1 litre)
(1 mole) * (0.0821 L-atm/mole* k)
= 1.60 * 10-11 litre
= 1.60 * 10-8 ml
This should be the minimum volume of CO2 needed to be formed in order to be detected in the vacuum system