Reaction enthalpy or reaction trope (thermo-11)

Think about it to you for each the following operations, whether or not each a increase or a decrease the entropy and the enthalpy of the chemical products [translation unavailable] to expected is (z.B. ΔHoR of which:0 and so on.):

1. CO₂(s) sublimated to CO₂(g)
2. Heating by CaCO₃(s)
3. CO₂(g) + CaO(s) → CaCO₃(s)
4. H₂O(s) → H₂O(l) → H₂O(g) → 0.5·O₂(g) + H₂(g)
5. Ba(OH)₂(s) + 2·NH₄SCN(s) → Ba(SCN)₂ + 2·NH₃(g) + 2·H₂O(l)
6. NH₃(g) + HCl(g) → NH₄Cl(s)

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• October 16, 2026 at 4:43 am #9556
    Exercise: thermo-11    

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  Think about it to you for each the following operations, whether or not each a increase or a decrease the entropy and the enthalpy of the chemical products [translation unavailable] to expected is (z.B. ΔHoR of which:0 and so on.):

  1. CO₂(s) sublimated to CO₂(g)
  2. Heating by CaCO₃(s)
  3. CO₂(g) + CaO(s) → CaCO₃(s)
  4. H₂O(s) → H₂O(l) → H₂O(g) → 0.5·O₂(g) + H₂(g)
  5. Ba(OH)₂(s) + 2·NH₄SCN(s) → Ba(SCN)₂ + 2·NH₃(g) + 2·H₂O(l)
  6. NH₃(g) + HCl(g) → NH₄Cl(s)

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    Exercise: thermo-11    

  ⓘ    🔄 Reload     🖨️ print           ◀  –   ▶     ?! Question/Answer ?!

  Think about it to you for each the following operations, whether or not each a increase or a decrease the entropy and the enthalpy of the chemical products [translation unavailable] to expected is (z.B. ΔHoR of which:0 and so on.):

  1. CO₂(s) sublimated to CO₂(g)
  2. Heating by CaCO₃(s)
  3. CO₂(g) + CaO(s) → CaCO₃(s)
  4. H₂O(s) → H₂O(l) → H₂O(g) → 0.5·O₂(g) + H₂(g)
  5. Ba(OH)₂(s) + 2·NH₄SCN(s) → Ba(SCN)₂ + 2·NH₃(g) + 2·H₂O(l)
  6. NH₃(g) + HCl(g) → NH₄Cl(s)

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  October 16, 2026 at 4:43 am #9557
  Solution:

  1. CO₂(s) sublimated to CO₂(g):

         ΔSoR of which:0, ΔHoR of which:0

         ΔSoR > 0, since CO₂ is transferred from solid (s) to gaseous (g)

         ΔHoR > 0, since CO₂ is first liquefied and then transferred to the gaseous state, endothermic process

  2. Heating of CaCO₃(s):

         ΔSoR of which:0, ΔHoR of which:0

         ΔSoR at an increase in temperature the particles move more forcefully (back and forth), dS therefore > 0

         ΔHoR > 0, since heating, i.e. energy must be invested, endothermal process

  3. CO₂(g) + CaO(s) → CaCO₃(s):

         ΔSoR [translation unavailable]0, ΔHoR [translation unavailable]0

         ΔSoR < 0, as two particles become a particle and partly transition from gas phase to solid phase.

         Experiment (or could be calculated), exothermic process, ΔHoR < 0

  4. H₂O(s) → H₂O(l) → H₂O(g) → 0.5·O₂(g) + H₂(g):

         ΔSoR of which:0, ΔHoR of which:0

         ΔSoR > 0, since transitions from solid → liquid → gaseous, more particles are also produced

         ΔHoR > 0, everyday experience: transfer from solid → liquid etc. requires energy, endothermal process

  5. Ba(OH)₂(s) + 2·NH₄SCN(s) → Ba(SCN)₂(aq) + 2·NH₃(g) + 2·H₂O(l):

         ΔSoR of which:0, ΔHoR of which:0

         ΔSoR of which:0, there from the two solids a liquid, a [translation unavailable] and in the water aquated Ba(SCN)₂ of which:

         Experiment, typical cold mixing. When mixing the two salts, the mixture is cooled, endothermic process, ΔHoR > 0

  6. NH₃(g) + HCl(g) → NH₄Cl(s):

         ΔSoR [translation unavailable]0, ΔHoR [translation unavailable]0

         ΔSoR < 0, from two (gas) particles becomes a particle

         ΔHoR < 0, but justification possible only with a calculation

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