Since you did not give a calculation,
I will just give an example. Suppose that you are to burn 5 kg of methane (CH4)
from 0 to 10°C. The specific heat capacity of methane is 4.475 kJ/kg-K.
H
= mCpT
H
= (5kg)( 4.475 kJ/kg-K)(10-0)
H = 223.75 kJ
Because the enthalpy is positive
in value, methane takes in heat.
Electron affinity is the energy released when an electron is accepted by a neutral atom forming a negative ion. Chlorine has the higher electron affinity because it readily accepts an electron to become more stable. On the other hand, sodium have to give up an electron to complete its valence shell.
