Answer:
a. ΔH⁸ = -1420 kJ/mol b. ΔH⁸ = -1144.84 kJ/mol
Explanation:
a.
C₂H₄ (g) + 3 O₂ (g) ------------------------ 4 CO₂ (g) + 2 H₂O (l) ΔH⁸ = ?
ΔH⁸f kJmol 52.47 0 -399.5 -285.83
ΔH⁸ = 2(-399.5) + 2 (-285.83) - (52.47)
ΔH⁸ = -1420 kJ/mol
b.
H₂S (g) + 3 O₂ (g) ---------------------- 2 H₂O (l) + 2 SO₂ (g)
ΔH⁸f kJmol -20.50 0 -285.83 -296.84
ΔH⁸ = 2(-285.83) + 2 (-296.84) - (-20.50)
ΔH⁸ = -1144.84 kJ/mol
According to this formula when:
ΔG = ΔH - TΔS = 0
∴ ΔS = ΔH/T
∴ ΔS = n*ΔHVap / Tvap
- when n is the number of moles = mass/molar mass
when the mass = 24.1 g
and the molar mass = 187.3764 g/mol
by substitution:
∴ n = 24.1 / 187.3764g/mol
= 0.129 moles
and ΔHvap is the molar enthalpy of vaporization is 27.49 kJ/mol
and Tvap is the temperature in Kelvin = 47.6 + 273 = 320.6 K
So by substitution, we will get the ΔS the change in entropy:
∴ΔS = 0.129 mol * 27490 J/mol / 320.6 K
= 11 J/K
Answer : The atom with the same number of neutrons as
is, 
Explanation :
- The given atom is,

Atomic mass number = 12
Atomic number = 6
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass number - Atomic number = 12 - 6 = 6
Now we have to determine the number of neutrons in the given options.
- In atom,

Atomic mass number = 9
Atomic number = 4
Atomic number = Number of protons = Number of electrons = 4
Number of neutrons = Atomic mass number - Atomic number = 9 - 4 = 5
- In atom,

Atomic mass number = 11
Atomic number = 5
Atomic number = Number of protons = Number of electrons = 5
Number of neutrons = Atomic mass number - Atomic number = 11 - 5 = 6
- In atom,

Atomic mass number = 13
Atomic number = 6
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass number - Atomic number = 13 - 6 = 7
- In atom,

Atomic mass number = 14
Atomic number = 7
Atomic number = Number of protons = Number of electrons = 7
Number of neutrons = Atomic mass number - Atomic number = 14 - 7 = 7
Therefore, the atom with the same number of neutrons as
is, 