The first excited state of a particular atom in a gas is 6.1 eV above the ground state. A moving electron collides with one of these atoms, and excites the atom to its first excited state. Immediately after the collision the kinetic energy of the electron is 3.2 eV. What was the kinetic energy of the electron just before the collision

The kinetic energy of the electron just before the collision is 9.3 eV.

Explanation:

We can find the kinetic energy of the electron before the collision can be found by energy conservation:

  (1)

Where:

: is the initial kinetic energy of the atom

: is the final kinetic energy of the atom = 6.1 eV +

: is the initial kinetic energy of the electron =?

: is the final kinetic energy of the electron = 3.2 eV

By solving equation (1) for we have:

Therefore, the kinetic energy of the electron just before the collision is 9.3 eV.

I hope it helps you!

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

bcde is the incorrect answer it is a