Answer:
They are held together by hydrogen bonds
Explanation:
Hydrogen bonds are special dipole-dipole attractions between polar molecules in which a hydrogen atom is directly joined to a highly electronegative atom(oxygen or nitorgen or fluorine).
Such molecules includes water, alkanoic acids, ammonia and amines.
A hydrogen nucleus has a high concentration of positive charge. The bond is actually an electrostatic attraction between the hydrogen atom of one molecule and the electronegative atom(O or N or F).
Hydrogen bonds are very effective in binding molecules into larger units. Most substances that joins with hydrogen bonds have a higher boiling point and lower volatility.
This is why we have a strong intermolecular bond between water molecules.
H2(g) +C2H4(g)→C2H6(g)
H-H +H2C =CH2→H3C-Ch3
2C -H bonds and one C-C bond are formed while enthalpy change (dH) of the reaction,
H-H: 432kJ/mol
C=C: 614kJ/mol
C-C: 413 kJ/mol
C-C: 347 kJ/mol
dH is equal to sum of the energies released during the formation of new bonds or negative sign, and sum of energies required to break old bonds or positive sign.
The bond which breaks energy is positive.
432+614 =1046kJ/mol
Formation of bond energy is negative
2(413) + 347 = 1173 kJ/mol
dH reaction is -1173 + 1046 =-127kJ/mol
Answer:
The energy of a vibrating molecule is quantized much like the energy of an electron in the hydrogen atom. The energy levels of a vibrating molecule are given by the equation: En=(n+21)hv where n is a quantum number with possible values of 1, 2, ... and v is the frequency of vibration.
Explanation:
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