Na2CO3(s) ---> 2Na+ (aq) + CO3^2- (aq)
When 15.0 grams od Na2CO3 are dissolved in 100g of water, the temperature of the solution increases from 25.0*C to 33.0*C. Calculate the change in enthalpy for the dissolving of sodium carbonate. Assume no heat lost to the surroundings and the solution has a specific heat capacity of 4.18 J/g*C.
Calorimetry I: Consider the dissolution of sodium carbonate?
2017-10-09 2:10 pm
回答 (1)
2017-10-09 3:49 pm
Na₂CO₃(s) → 2Na⁺(aq) + CO₃²⁻(aq)
Heat given off in dissolution = [(100 + 15) g] × (4.18 J/g°C) × [(33.0 - 25.0) °C] = 3846 J
No. of moles of Na₂CO₃ = 15.0 g / [(23.0×2 + 12.0 + 16.0×3) g/mol] = 0.1415 mol
Enthalpy change for the dissolving of Na₂CO₃ = -(3846 J) / (0.1415 mol) = -27200 J/mol = -27.2 kJ/mol
Heat given off in dissolution = [(100 + 15) g] × (4.18 J/g°C) × [(33.0 - 25.0) °C] = 3846 J
No. of moles of Na₂CO₃ = 15.0 g / [(23.0×2 + 12.0 + 16.0×3) g/mol] = 0.1415 mol
Enthalpy change for the dissolving of Na₂CO₃ = -(3846 J) / (0.1415 mol) = -27200 J/mol = -27.2 kJ/mol
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