amount of lattice enthalpy needed to break the lattice structure of ionic

Amount of lattice enthalpy needed to break the

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amount of lattice enthalpy needed to break the lattice structure of ionic compounds is compensated by the hydration enthalpies of the ions and the increase in entropy as the solution becomes more disordered. Δ H solution = Δ Hlattice + Δ Hhydration ❑❑
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3. The enthalpy of solution of an ionic compound can be calculated from its lattice enthalpy and the enthalpies of hydration of the individual ions. Use the information shown below to calculate: a. The enthalpy of solution of solid ammonium chloride [1 mark] Δ H solution = Δ Hlattice + Δ Hhydration ❑❑ ¿ ( g ) + ¿ ( g )+ Cl ¿ NH 4 Cl ( s )+ 705 kJ / mol→ NH 4 ¿ + ¿ ( aq )+ 307 kJ / mol + ¿ ( g )+( aq ) →NH 4 ¿ NH 4 ¿ ¿ ( aq )+ 381 kJ / mol ¿ ( g )+( aq ) →Cl ¿ Cl ¿ Δ H solution ( NH 4 Cl )= 705 kJ / mol +(− 307 kJ / mol )+(− 381 kJ / mol ) ❑❑ Δ Hsolution ( NH 4 Cl )=+ 17 kJ / mol b. The enthalpy of solution of solid ammonium nitrate [1 mark] Δ H solution = Δ Hlattice + Δ Hhydration ❑❑ ¿ ( g ) + ¿ ( g )+ NO 3 ¿ NH 4 NO 3 ( s )+ 646 kJ / mol→ NH 4 ¿ + ¿ ( aq )+ 307 kJ / mol + ¿ ( g )+( aq ) →NH 4 ¿ NH 4 ¿ ¿ ( aq )+ 314 kJ / mol ¿ ( g )+( aq ) → NO 3 ¿ NO 3 ¿ Δ H solution ( NH 4 NO 3 )= 646 kJ / mol +(− 307 kJ / mol )+(− 314 kJ / mol ) ❑❑
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Δ Hsolution ( NH 4 NO 3 )=+ 25 kJ / mol 4. *In 2001, Nescafe launched a self-heating can of coffee, called Hot When You Want. To heat up the coffee, a button was pressed which mixed the heating ingredients in a shell outside the can containing the coffee. The can warms up 210 cm3 of coffee by 40 °C. A single step mixed
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  • Fall '14
  • Pell, Wendy

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