(a) Write the balanced chemical equation that represents the standard heat of formation of H2CO(g) at 298 K. Use the pull-down boxes 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 283 kJ at 298 K.

KO2(s)--> K(s) + O2(g)

What is the standard heat of formation of KO2(s)?