Barron's Science 360 by Mark Kernion

Author:Mark Kernion
Language: eng
Format: epub
Publisher: Barrons Educational Series
Published: 2021-07-13T00:00:00+00:00

EXAMPLE

How much heat is liberated when 40.0 g of H2(g) reacts with excess O2(g)?

SOLUTION

The reaction equation is

This represents 1 mol or 2 g of H(g) forming 1 mol of H2O(g)

Since each mole gives off –241.8 kJ, then

Notice that the physical state of each participant must be given since the phase changes involve energy changes.

Combustion reactions produce a considerable amount of energy in the form of light and heat when a substance is combined with oxygen. The heat released by the complete combustion of one mole of a substance is called the heat of combustion of the substance. Heat of combustion is defined in terms of one mole of reactant, whereas heat of formation is defined in terms of one mole of product. All substances are in their standard state. The general enthalpy notation, ΔH, applies to heats of reaction, but with the addition of a subscripted c, ΔHc, refers specifically to heat of combustion.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.