Use and interpret standard heats of formation. Close Problem Question Content Area (a) Write the balanced chemical equation that represents the standard heat of formation of KClO4(s) at 298 K. Be sure to specify states. Write fractions with a slash, such as 1/2 for one half. If a box is not needed leave it blank. + + (b) The standard enthalpy change for the following reaction is 561 kJ at 298 K. Sn(OH)2(s) Sn(s, white) + O2(g) + H2(g) What is the standard heat of formation of Sn(OH)2(s)? kJ/mol