Question

Write the equation for the formation of a fluoride anion from a fluorine atom. If the electron affinity of the fluorine atom is 328 kJ/mol, what is q when 2.5 mol of fluoride anions are formed from fluorine atoms? How much energy is released when one F atom accepts an electron?

Answer 1

Answer:

Part A. F + e⁻ → F⁻

Part B. -820 kJ

Part C. -5.45x10⁻²² kJ

Explanation:

Part A

The fluoride anion is formed when fluorine accepts an electron:

F + e⁻ → F⁻

Part B

The electron affinity is the energy necessary for the atom to accept 1 electron, which is exothermic, so it's negative. The total energy q is the electron affinity multiplied by the number of moles:

q = -328 kJ/mol * 2.5 mol

q = -820 kJ

Part C

By the Avogadros' number

1 mol --------- 6.02x10²³ atoms

x --------- 1 atom

By a simple direct three rule:

x = 1.66x10⁻²⁴ mol

So, the energy for 1 atom is:

q = -328 kJ/mol * 1.66x10⁻²⁴ mol

q = -5.45x10⁻²² kJ