Investigation of Action of Saliva and 3 M Hydrochloric Acid in Two Carbohydrate Solutions

In: Science

Submitted By sathes
Words 2559
Pages 11
Centre for Foundation Studies, UTAR

1

2

Chapter Scopes
• Endothermic & Exothermic reactions
• Enthalpy changes: ∆H of formation,
combustion, hydration, neutralization,
atomization.

CHAPTER 5

Chemical Energetic /
Thermochemistry

• Lattice energy, electron affinity
• Heat of fusion and vaporization
• Hess’ Law
• Born-Haber cycles
• Calorimetry

© 2006 Brooks/Cole - Thomson

© 2006 Brooks/Cole - Thomson

3

Energy & Chemistry

4

Thermochemistry
• Thermochemistry is the study of heat (energy)
change/transfer in a chemical reaction.

• ENERGY is the capacity to do work or transfer
heat.
• HEAT is the transfer of thermal energy
between two objects because of their
difference in temperature.

Heat energy is associated
with molecular motions.

Other forms of energy
light
electrical
kinetic and potential

Heat transfers until thermal equilibrium is
established.
∆T measures energy transferred.

© 2006 Brooks/Cole - Thomson

© 2006 Brooks/Cole - Thomson

System and Surroundings

5

System and Surroundings

6

Vacuum
jacket

• SYSTEM
– The object under
study
• SURROUNDINGS
– Everything outside
the system
© 2006 Brooks/Cole - Thomson

FHSC1114 Physical Chemistry

open
Exchange: mass & energy

closed
energy

isolated
nothing

© 2006 Brooks/Cole - Thomson

1

Centre for Foundation Studies, UTAR

Directionality of Heat Transfer

7

Directionality of Heat Transfer

• Heat always transfer from hotter object to
cooler one.

• Heat always transfers from hotter object to
cooler one.

• EXOthermic: heat transfers from SYSTEM to
SURROUNDINGS.

8

• ENDOthermic: heat transfers from
SURROUNDINGS to the SYSTEM.

T(system) goes down
T(surr) goes up
© 2006 Brooks/Cole - Thomson

T(system) goes up
T(surr) goes down
© 2006 Brooks/Cole - Thomson

UNITS OF ENERGY

Heat…...