Introductory Chemistry: A Foundation, 6th Ed. Introductory Chemistry, 6th Ed. Basic Chemistry, 6th E - PowerPoint PPT Presentation

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Introductory Chemistry: A Foundation, 6th Ed. Introductory Chemistry, 6th Ed. Basic Chemistry, 6th E

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Figure 10.4: The water samples have the same ... Medium size Candy bar contains 240 Calories. ... Candy Serving Size Calories. Chocolate coated peanuts 1oz 155 ... – PowerPoint PPT presentation

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Title: Introductory Chemistry: A Foundation, 6th Ed. Introductory Chemistry, 6th Ed. Basic Chemistry, 6th E


1
Chapter 10Energy
2
What is Ahead?
  • To understand the general properties of energy.
  • To understand the concepts of temperature and
    heat.
  • To understand the units of energy.
  • To consider the energy resources of our world.

3
Energy
  • Energy Capacity to do work or supply energy.
  • 1. Potential Energy stored energy.
  • Example a coiled spring have potential energy
    waiting to be released.
  • 2. Kinetic Energy energy of motion.
  • Example when the spring uncoil potential energy
    is converted to the kinetic energy.

4
Figure 10.1 (a) In the initial positions, ball A
has a higher potential energy than ball B. (b)
After A has rolled down the hill, the potential
energy lost by A has been converted to random
motions of the components of the hill
(frictional heating) and to an increase in the
potential energy of B.
5
Conservation of Energy
  • Just like matter, energy cannot be created or
    destroyed but it can converted from one form to
    another.
  • This is the law of conservation of energy.
  • There are six forms of energy heat, light,
    electrical, mechanical, chemical, and nuclear.

6
Forms of Energy
  • Kinetic energy
  • Potential energy
  • Solar energy
  • Radiant energy
  • Thermal energy
  • Nuclear energy
  • Electrical energy
  • Chemical energy

7
Energy Conversion
  • Identify the energy conversions in each of the
    following
  • Radioactive uranium vaporizes water to steam.
    _________
  • Steam drives a turbine. ___________
  • A turbine spins and drives an electrical
    generator. __________
  • Flashlight. ___________
  • Solar calculator. ____________
  • Lead-acid battery. ___________
  • Electrical heater. ____________

8
Answers
  • Radioactive uranium vaporizes water to steam.
    Nuclear to thermal.
  • Steam drives a turbine. Thermal to mechanical.
  • A turbine spins and drives an electrical
    generator. Mechanical to electrical.
  • Flashlight. Chemical to radiant.
  • Solar calculator. Radiant to electrical.
  • Lead-acid battery. Chemical to electrical
  • Electrical heater. Electrical to thermal.

9
Temperature and Heat
  • Temperature is a measure of the random motion of
    the components of a substance.
  • Heat a flow of energy due to a temperature
    difference.

10
Figure 10.3 The H2O molecules in hot water have
much greater random motions than the H2O
molecules in cold water.
11
Figure 10.4 The water samples have the same
temperature (50. C) and have the same random
motions.
12
Units of Energy
  • calorie (cal metric system unit) the amount of
    energy required to raise the temperature of one
    gram of water by one Celsius degree.
  • Units are
  • calorie (cal) and joule (J)
  • 1 cal 4.184 J, 1 kcal 4.184 k
  • 1000 cal 1 kcal (kilocalorie)
  • 1000 J 1 kJ
  • Calorie (food calorie 1 Cal 1000 cal)

13
Specific Heat
  • The specific heat of a substance is the amount of
    heat required to bring about a change in
    temperature.
  • The larger the specific heat, the more heat is
    required to raise the temperature of the
    substance.

14
Examples of specific heat
Iron 0.108 cal/g.degree Copper 0.0920
cal/g.degree Water 1.00 cal/g.degree Air 0.241
cal/g.degree
15
Food Calories
  • Medium size Candy bar contains 240 Calories.
    That is 240,000 calories or about 1.0 million
    joule. The fact of the matter is, that it takes
    1 joule of energy to lift 1 small apple of 1
    Newton weight (about 0.25 pound) for a distance
    of 1 meter. That concludes, some one should lift
    that apple one million times for a distance of 1
    meter to be able to burn all the calories
    generated from the snack bar.

16
  • Candy Serving Size Calories
  • Chocolate coated peanuts 1oz 155
  • Hershey bar 1 (1.5oz) 240
  • Hershey kisses 9 (1.5oz) 220
  • M M's, plain 1 pkt 230
  • M M's, peanut 1 pkt 250
  • Skittles 1 pkt (2.8oz) 250
  • Snickers bar 1 bar (2.1oz) 280

17
Energy and Our World
  • Petroleum and natural gas
  • Coal
  • New energy sources

18
Hydrocarbons
19
Methane molecule
20
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21
Figure 10.7 Energy sources used in the US.
22
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23
Coal is an important and plentiful fuel in the
United States, currently furnishing approximately
20 of our energy.
Corbis
24
Figure 10.8 The function of the earth's
atmosphere.
25
Figure 10.9 The atmospheric CO2 concentration
over the past1000 years, based on ice core data
and direct readings (since 1958).
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