Entropy - exam practice

H₂O_(s) ➔ H₂O_(l)

Hg_(l) ➔ Hg_(g)

H₂O_(l) + HCl_(g) ➔ H₃O⁺_(aq) + Cl^-_(aq)

C(graphite) ➔ C(diamond)

-219.1

-88.5

+88.5

+219.1

enthalpy increases and entropy decreases

enthalpy decreases and entropy increases

enthalpy decreases and entropy decreases

enthalpy increases and entropy increases

CaCO_3(s) ➔ CaO_(s) + CO_2(g)

N_2(g) + 3H_2(g) ⇌ 2NH_3(g)

3CO_2(g) + 3H₂O_(g) ➔ C₃H_8(g) + 5O_2(g)

SO_2(g) + H₂O_2(l) ➔ H₂SO_4(l)

CaCO_3(s) ➔ CaO_(s) + CO_2(g)

H₂O_(l) ➔ H₂O_(s)

NH_3(g) + HCl_(g) ➔ NH₄Cl_(s)

C₂H₅OH_(l) + SOCl_2(l) ➔ C₂H₅Cl_(l) + SO_2(g) + HCl_(g)

CaCO_3(s) ➔ CaO_(s) + CO_2(g)

H₂O_(l) ➔ H₂O_(g)

N_2(g) + 3H_2(g) ⇌ 2NH_3(g)

2S₂O₃^2-_(aq) + I_2(aq) ➔ S₄O₆^2-_(aq) + 2I^-_(aq)

$\mathrm{\Delta }{S}_{system}-\frac{\mathrm{\Delta }H}{T}$

$\mathrm{\Delta }{S}_{surroundings}+\frac{\mathrm{\Delta }H}{T}$

$\mathrm{\Delta }{S}_{surroundings}-\frac{\mathrm{\Delta }H}{T}$

$\mathrm{\Delta }{S}_{system}+\frac{\mathrm{\Delta }H}{T}$

ΔS_system is negative

ΔS_total is negative

ΔH is positive

ΔS_surroundings is positive

change W never occurs

change X could be the reaction of a solid carbonate with an acid

change Y could be a precipitation reaction

change Z could be the condensation of a gas to a liquid

the reaction is always feasible

the reaction is feasible above a certain temperature

the reaction is feasible below a certain temperature

the reaction is never feasible

the reaction is at equilibrium

the reaction is spontaneous

the formation of reactants is favoured

the formation of products is favoured

if ΔH < 0, the reaction is always spontaneous

if ΔH > 0, the reaction is never spontaneous

if ΔS_system < 0, the reaction can be spontaneous if temperature is low enough

if ΔS_system < 0, the reaction can be spontaneous if temperature is high enough

ΔS_total = negative, K > 1

ΔS_total = negative, K < 1

ΔS_total = positive, K < 1

ΔS_total = positive, K > 1

ΔH^⦵ = positive, ΔS^⦵_system = negative

ΔH^⦵ = negative, ΔS^⦵_system = positive

ΔH^⦵ = positive ΔS^⦵_system = positive

ΔH^⦵ = negative, ΔS^⦵_system = negative

S_system = minimum, S_total = minimum

S_system = maximum, S_total = minimum

S_system = maximum, S_total = maximum

S_system = minimum, S_total = maximum

the forward reaction is more spontaneous below 300 K

entropy is higher in the products than in the reactants

equilibrium shifts left as temperature increases

K decreases as temperature increases