Solid carbon reacts with carbon dioxide according to at 298 K

CHEMISTRY · Single correct · A Level · Chemistry · Gaseous equilibria (Kp) · Gaseous equilibria (Kp)

Problem

Solid carbon reacts with carbon dioxide according to

\text{C}(s)+\text{CO}_2(g)\rightleftharpoons2\,\text{CO}(g)

at 298 K. Which statement best describes the numerical relationship between

K_p

and

K_c

for this reaction at that temperature? (a)

K_p

equals

K_c

because solids do not appear in either equilibrium expression. (b)

K_p

is greater than

K_c

because the reaction produces more moles of gas than it consumes, so

K_p = K_c(RT)

. (c)

K_p

is less than

K_c

because

K_p = K_c/(RT)^{\Delta n}

when

\Delta n>0

. (d)

K_p

and

K_c

cannot be related unless the total pressure is specified.