Lesson: Hess Cycles Using Enthalpies of Formation Chemistry

In this lesson, we will learn how to calculate reaction enthalpies by comparing the standard enthalpies of formation of the reactants and the products.

Sample Question Videos

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Lesson Worksheet

Q1:

Using the data below, calculate to 3 significant figures the standard molar enthalpy of combustion of diborane .

Substance
	36.4

Q2:

Using the data in the table, calculate, to the nearest kilojoules per mole, the standard enthalpy of combustion of hydrazine . One of the products of the reaction is nitrogen.

Substance
(kJ/mol)	50.63

Q3:

Using the data in the table, calculate, to the nearest kilojoules per mole, the standard enthalpy of combustion of methane.

Substance
(kJ/mol)