Explain how the energy changes when the atp molecule is converted to adp and
phosphate.

There is a release of high negative free energy when ATP is converted to ADP and pi.

Explanation:

ATP is known as the energy currency of the cell because ATP  provides energy to the cell to carry out various biochemical and physiological processes such as muscle contraction ,membrane transport etc.

   When ATP undergo hydrolysis to generate ADP and pi at that time a high negative free energy is generated whose value is -30.5 kj/mol or -7.3 kcal/mol.