Respuesta :
Answer:
The enthalpy change per mole of sodium when sodium reacts with water is 28.36 kJ
Step-by-step explanation:
The given parameters are;
Mass of sodium = 8 grams = 0.008 kg
Volume of water = 227 cm³ = 0.000227 m³
Initial water temperature, T₁ = 298 K
Final water temperature, T₂ = 308.4 K
Specific heat capacity of water = 4.18 J/(K·g)
Density of water = 1000 kg/m³
Mass of water = 1000×0.000227 = 0.227 kg = 227 g
Heat change, ΔH = m×c×ΔT = m×c×(T₂ - T₁)
ΔH = 227*4.18*(308.4 - 298) = 9868.144 J = 9.868 kJ
Molar mass of sodium = 22.989769 g/mol
Therefore, 8 grams contains;
8/22.989769 = 0.348 moles of Na
Which gives the enthalpy change per 0.348 moles of Na when sodium reacts with water = 9.868 kJ
Therefore, when one mole of Na reacts with water we have;
The enthalpy change per 0.348/0.348 = 1 mole of Na when sodium reacts with water = 9.868 kJ/0.348 = 28,358.3 J = 28.36 kJ.
