The ionisation enthalpy of sodium is 5.14 eV. How many k cal of energy is required to ionise all atoms present in one gram of gaseous Na atoms?

Explanation

1e V atom`""^(-1)` = 23 k cal `mol."^(-1)`
Energy required to ionise all atoms of 23 grams (one mole ) of gaseous Na atoms `= 23 xx 5.14 k cal `
Energy required for ionisation of all atoms present
in one gram of gaseous Na atom `= (23 xx 5.14)/(23)`
`=5.14` k cal .