Please answer all the questions in the picture
Answers
Extensive properties of a substance depend on the amount of matter in that substance. They depend on the sample size. Volume, mass, pressure, resistance are extensive properties.
Intensive properties are fundamental properties of the substances. They depend on the chemical composition or the nature of the substance. They do not depend on the amount of matter of the sample we have. Density, color, hardness, boiling point, resistivity, conductivity, specific heat, melting point etc. are intensive properties.
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ΔG = ΔH – T ΔS = 80,000 * 2 moles – 400 * 120 = 112 kJ
ΔG = - RT Ln K
Ln K = - ΔG/RT = - 112,000 /400 /8.314 = - 33.67
K = 2.364 * 10^-14 units.
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Gibbs free energy is defined as : G = H – T S
Then the change in free energy: ΔG = ΔH – T ΔS - S ΔT
For an isolated system at constant temperature and pressure, Q = ΔH = 0, as the heat does not escape the system. We consider systems at melting point or boiling point for example, which are in equilibrium at constant pressure and temperature. ΔS represents the change in entropy (internal, total) of the system.
Thus ΔG = - T ΔS
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Ethene combustion: C2H4 (g) + 3 O2 (g) ==> 2 CO2 + 2 H2 O (g)
To break one C=C bond, four C-H bonds, three O=O bonds. To make four C=O bonds, four O-H bonds.
ΔH = 4* 724 + 4* 460 – 619 – 4* 414 – 3 * 499 = 964 kJ/mole of Ethene
Heat Energy is released.
But as per data from standard references, the ΔH of combustion seems to be 1411 kJ/mole. There is a difference.
C=O: 799kJ/mol, O-H: 463 kJ/mol, C=C: 602 kJ/mol, C-H: 413 kJ/mol, O=O: 498 kJ/mol
ΔH = 4*799 + 4 * 463 – 602 – 4 * 413 – 3 * 498 = 1300 kJ/mol