Molarity is defined as the number of moles present in one liter of solution. Given the mass of NH₃ is 2.35 g and its molar mass is 17 g/mol, the moles of NH₃ in 2.35 g can be calculated as 2.35 g / 17 g/mol = 0.138 mol. Consequently, in a 0.05 L solution, the number of moles amounts to 0.138 mol. Therefore, the concentration in 1 L is: 0.138 mol / 0.05 L x 1L = 2.76 mol. Thus, the molarity of NH₃ is 2.76 M.
Based on the equation:
ΔG = ΔH - TΔS = 0
It follows that ΔS = ΔH/T
So, ΔS = n*ΔHVap / Tvap
- where n represents the number of moles calculated as mass/molar mass
For a mass of 24.1 g
and a molar mass of 187.3764 g/mol
substituting gives:
∴ n = 24.1 / 187.3764g/mol
= 0.129 moles
The molar enthalpy of vaporization, ΔHvap, is 27.49 kJ/mol
The temperature in Kelvin, Tvap = 47.6 + 273 = 320.6 K
After substitution, we compute ΔS, the change in entropy:
∴ΔS = 0.129 mol * 27490 J/mol / 320.6 K
= 11 J/K
