Zadanie 4e
Ethene reacts with water in the presence of an acid catalyst at room temperature. C2H4(g) + H2O(l) → C2H5OH(l) ΔH⊖ = −44 kJ mol−1 (i) Calculate the change in entropy, ΔS⊖, for this reaction in…
Entropy and standard entropy change
Explain entropy as the dispersal of matter and energy, predict whether a change increases or decreases entropy from states of matter and numbers of gas molecules, and calculate the standard entropy change ΔS from standard entropy values in the data booklet.
Tę umiejętność sprawdzają 23 zadania wzorowane na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 23 Otwórz w wyszukiwarce z filtrami
Zadanie 22
In which reaction will there be a decrease in entropy? A. NH4NO3(s) → NH4NO3(aq) B. CaCO3(s) → CaO(s) + CO2(g) C. 2 H2(g) + O2(g) → 2 H2O(l) D. N2O4(g) → 2 NO2(g)
Zadanie 22
Under which temperature conditions is ΔG⊖ negative for this reaction? CaCO3(s) → CaO(s) + CO2(g) ΔH⊖ = +178 kJ mol−1 A. Low temperatures only B. High temperatures only C. Any temperatures D. No temperatures
Zadanie 21
Which change results in a decrease in entropy? A. 2 NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g) B. I2(s) → I2(g) C. CO(g) + 2 H2(g) → CH3OH(l) D. KNO3(s) → KNO3(aq)
Zadanie 23
For which of these changes is ΔS negative? A. 2 SO2(g) + O2(g) → 2 SO3(g) B. NaNO3(s) → NaNO3(aq) C. Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) D. CuCO3(s) → CuO(s) + CO2(g)
Zadanie 25
Which reaction has the largest positive entropy change? A. 2 SO2(g) + O2(g) → 2 SO3(g) B. NH4Cl(s) → NH3(g) + HCl(g) C. H2(g) + Cl2(g) → 2 HCl(g) D. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
Zadanie 4b
(i) Using section 12 of the data booklet, determine the standard enthalpy change of the reaction, in kJ mol−1. (ii) A value obtained from bond enthalpies is less accurate than one obtained from enthalpies of formation. State two reasons why.…
Zadanie 24
Which reaction is expected to have the largest decrease in entropy? A. 2 H2S(g) + SO2(g) → 3 S(s) + 2 H2O(l) B. 2 C4H10(g) + 13 O2(g) → 8 CO2(g) + 10 H2O(l) C. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) D. 2 CO(g) + O2(g) → 2 CO2(g)
Zadanie 5d
Pentadecane can be cracked into smaller molecules. Consider the reaction: C15H32(g) → 3 C4H8(g) + C3H8(g) where C4H8 is but-1-ene. (i) Use the bond enthalpies in section 12 of the data booklet to determine ΔH⊖ for this reaction.…
Zadanie 3f
Use section 13 of the data booklet and the standard molar entropy of hydrogen, S⊖(H2(g)) = +130.7 J K−1 mol−1, to calculate ΔS⊖ for the forward reaction, in J K−1.
Zadanie 17
Which change results in the greatest decrease in entropy? A. CaCO3(s) → CaO(s) + CO2(g) B. NaNO3(s) → Na+(aq) + NO3−(aq) C. H2O(l) → H2O(g) D. N2(g) + 3 H2(g) → 2 NH3(g)
Zadanie 4d
Sulfuryl chloride, SO2Cl2, is made industrially from sulfur dioxide and chlorine in the presence of an activated carbon catalyst. SO2(g) + Cl2(g) ⇌ SO2Cl2(g) ΔH⊖ < 0 (i) Sketch a potential energy profile for the forward reaction,…
- Tabela do uzupełnienia
Zadanie 2d
Sulfur trioxide is manufactured industrially by the oxidation of sulfur dioxide. 2 SO2(g) + O2(g) ⇌ 2 SO3(g) ΔH⊖ = −198.0 kJ mol−1 (i) Outline what is meant by dynamic equilibrium. (ii) Deduce the Kc expression for this…
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Zadanie 2a
In air, sulfur dioxide can be oxidized to sulfur trioxide. The reaction is reversible, and at high temperature it reaches equilibrium in a closed container. 2 SO2(g) + O2(g) ⇌ 2 SO3(g) (i) At 600 °C the equilibrium constant, K, for this reaction is…
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Zadanie 16
Which pair of changes both involve an increase in entropy? A. N2(g) + 3 H2(g) → 2 NH3(g) and H2O(l) → H2O(s) B. CaCO3(s) → CaO(s) + CO2(g) and CO2(g) → CO2(s) C. Ag+(aq) + Cl−(aq) → AgCl(s) and…
Zadanie 2e
Calculate the standard entropy change, ΔS⊖, of the reaction, using section 13 of the data booklet and the values given:
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Zadanie 2e
Calculate ΔS⊖ for the forward reaction, using the values given below together with section 13 of the data booklet.
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Zadanie 4a
(i) Calculate the enthalpy change of this reaction using section 13 of the data booklet together with the values given below: (ii) Outline why the entropy change of this reaction is expected to be small. (iii) Ignoring any entropy change, estimate the…
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Zadanie 4a
(i) Calculate the enthalpy change for this reaction, using section 13 of the data booklet and the values given below. (ii) Outline why the entropy change of this reaction is expected to be small. (iii) Ignore the entropy change. Use your answer to (i) together…
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Zadanie 3c
The standard free energy change, ΔG⊖, for the production of methanol is −44.0 kJ at 298 K and the standard enthalpy change, ΔH⊖, is −114 kJ. (i) State, with a reason, whether the production of methanol is spontaneous at 298 K.…
- Materiał graficzny
Zadanie 4d
Consider the formation of gaseous nitrogen dioxide from liquid dinitrogen tetroxide. N2O4(l) → 2 NO2(g) ΔH⊖ = +85.9 kJ mol−1 (i) Calculate the entropy change of the reaction, ΔS⊖, in…
- Tabela do uzupełnienia
Zadanie 17
In which reaction does the entropy of the system decrease? A. 2 H2(g) + O2(g) → 2 H2O(l) B. CaCO3(s) → CaO(s) + CO2(g) C. N2O4(g) → 2 NO2(g) D. KNO3(s) → K+(aq) + NO3−(aq)
Zadanie 16
Which substance has the highest standard molar entropy, S⊖, at 298 K? A. NaCl(s) B. H2O(l) C. CH4(g) D. C2H6(g)