This is an involved process here is a simple overview. The Sanitizer level has to be down to 15ppm or less so wait for the level to drop on its own before proceeding. Once the level is at 15ppm add 2 pounds of Potassium Monopersulfate per 10,000 gallons of pool water each day for 3 days. Then have the water rechecked the level should be below 15ppm. Next shock the pool with 2 pounds of 65% available Calcium Hypochlorite. Mix this 1-pound at a time in a plastic bucket and pour the liquid into the pool. Do not let any granular get into the pool, only the liquid. The pool Will turn green, but should go back to blue after 24 hours. After 24 hours if you have a sand filter change the sand in the filter. If you have a DE or cartridge filter clean the grids or filter cartridge in a solution for cleaning baquacil filters. You may now start using chlorine. Keep in mind that for the next several shock treatments the pool will turn green and then go back to blue.
You need to know the ∆H of this reaction, or the enthalpy change. If you know the enthalpy change, then convert the 6.44 g of sulfur to moles, and use stoichiometry to determine what fraction of a mole was reacted, and multiply that time the value of ∆H of the reaction
$5,977.89 to be exact.