Enthalpy lecture notes random

Enthalpy lecture notes random - Chem 103, Section F0F Unit...

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Chem 103, Section F0F Unit I - An Overview of Chemistry Lecture 5 • Energy and matter • Energy and change • Enthalpy Lecture 5 - Energy and Matter This topic will be dealt with in some detail in Chem 104, however, it will be helpful for us to have some introduction to the topic in Chem 103. • Reading in Silberberg - Chapter 1, pp. 8-10 The Importance of Energy in the Study of Matter - Chapter 6, Section 1 Forms of Energy and Their Interconversion - Chapter 6, Section 2 Enthalpy: Heats of Reaction and Chemical Change 2 Lecture 5 - Energy and Matter Both physical and chemical changes are accompanied by changes in energy. • We have already looked at two forms of energy - Kinetic energy (K.E.) - Potential energy (P.E.) • We have seen how these two forms of energy can transform from one to the other. 3 Lecture 5 - Energy and Matter 4 Lecture 5 - Energy and Change 5 In lab we saw how chemical changes can be accompanied by a change in energy that is manifested by either an absorption or a release of heat : H 3 C 6 H 5 O 7 + NaHCO 3 NaH 2 C 6 H 5 O 7 + CO 2 + H 2 O citric acid sodium bicarbonate sodium citrate carbon dioxide water heat absorbed (endothermic) Mg + 2 HCl MgCl 2 + H 2 magnesium hydrochloric acid magnesium chloride hydrogen heat released (exothermic) Lecture 5 - Energy and Change 6 Heat is one of the ways that energy can be transferred from one place to another Heat and temperature are related. • Temperature is used to measure how hot or cold an object is - Heat flows spontaneously from hot regions to cold ones. - When an object absorbs heat, it gains energy - When a object release heat, it loses energy. Hot Cold heat
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Lecture 5 - Energy and Change 7 Heat is also transferred along with physical changes • For example, the melting of ice • In this case the heat does not go to change the temperature by rather to change the physical state Lecture 5 - Energy and Change 8 Another way that energy can be transferred from one region to another is through work. • One definition used for energy is
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Enthalpy lecture notes random - Chem 103, Section F0F Unit...

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