Dalton s Atomic Model

Transcription

1 MATERIAL WORLD

2 John Dalton Dalton s Atomic Model Atoms are indivisible (a solid sphere) Atoms of the same element are identical

3 John Dalton Dalton s Atomic Model Atoms of different elements differ in size, mass, and other properties

4 John Dalton Dalton s Atomic Model Atoms of different elements can combine to form compounds

5 Dalton s Atomic Model Atoms are neither created nor destroyed in chemical reactions Reactants Hydrogen + Oxygen Product Water (Atoms are merely rearranged)

6 Dalton s Atomic Model Conservation of Matter Reactants Hydrogen + Oxygen Product Water (Atoms are merely rearranged)

7 J. J. Thomson s Atomic Model

8 KNOW THOMSON S CATHODE RAY EXPERIMENT AND THIS LED TO THE DISCOVERY OF THE ELECTRON

9 E. Rutherford Atom is mostly empty space Atoms contain a tiny (positive) nucleus. (Gold Foil Experiment)

10 KNOW RUTHERFORD S GOLD FOIL EXPERIMENT AND HOW IT SHOWED THAT THE ATOM WAS MOSTLY EMPTY SPACE +

11 NIELS BOHR ( )

12 Recall: Rutherford s Atomic Model Electrons orbit in a cloud around the nucleus

13 Rutherford s Atomic Model Electrons orbit in a cloud around the nucleus Electrons can t orbit just anywhere around the nucleus We need a quantum theory to explain the orbits. - -

14 After analyzing the spectral lines emitted by hydrogen atoms, I ve come to the following conclusion

15 Bohr Atomic Model The electrons orbit the nucleus in specific energy levels + 1 st energy level

16 Bohr Atomic Model The electrons orbit the nucleus in specific energy levels + 2 nd energy level

17 Bohr Atomic Model The electrons orbit the nucleus in specific energy levels + 3 rd energy level

18 Bohr Atomic Model The electrons orbit the nucleus in specific energy levels + 4 th energy level ( and more )

19 Bohr Atomic Model Energy levels are also referred to as: Shells, Layers, Orbits. + 4 th energy level ( and more )

20 Bohr Atomic Model An electron can orbit in any of the layers; but not between the layers + Not here Here or here

21 Bohr Atomic Model Electrons can jump from one layer to another They need more energy to jump to layers further out + + Energy

22 Bohr Atomic Model Electrons can jump from one layer to another They need more energy to jump to layers further out + + Energy

23 Bohr Atomic Model Electrons can jump from one layer to another They need more energy to jump to layers further out + They release energy when they jump closer in

24 Bohr Atomic Model Electrons can jump from one layer to another + Energy They release energy when they jump closer in

25 Bohr Atomic Model Electrons tend to orbit in layers that require the least amount of energy + Energy

26 Bohr Atomic Model The 1 st layer can only hold 2 electrons + This layer is filled first

27 Bohr Atomic Model The 2 nd layer can hold up to 8 electrons +

28 Bohr Atomic Model The next 8 electrons will go in the 3 rd layer +

29 Bohr Atomic Model The next 2 electrons will go in the 4 th layer +

30 Bohr Atomic Model The first 20 electrons orbiting the nucleus fill the layers in the order:

31 Bohr Atomic Model The nucleus of an atom contains positively charged protons Negatively charged electrons orbit the nucleus in specific energy levels + Atoms are normally neutral Normally, # electrons = # protons

32 Bohr Atomic Model If an atom has 1 proton in the nucleus it will have 1 electron orbiting the nucleus That electron will orbit in the 1 st energy level 1+

33 Bohr Atomic Model If an atom has 6 protons in the nucleus it has 6 electrons orbiting the nucleus 6+ 2 electrons in the 1 st energy level (1 st layer is full) Remaining 4 electrons in the 2 nd energy level

34 Bohr Atomic Model If an atom has 15 protons in the nucleus it has 15 electrons orbiting the nucleus electrons in the 1 st energy level 8 electrons in the 2 nd energy level Last 5 electrons in the 3 rd layer

35 UNDERSTAND THE LAW OF CONSERVATION OF MASS AND BE ABLE TO DO THE CALCULATIONS Carbon dioxide Calcium carbonate Word equation 110 g g 250 g + 45 g 295 g 295 g

36 BE ABLE TO READ THE PERIODIC TABLE; KNOW HOW TO DETERMINE THE NUMBER OF PROTONS, ELECTRONS, VALENCE ELECTRONS, ENERGY SHELLS

37 IA Groups VIIIA IIA Elements in the same group have the same number of valence electrons IIIA IVA VA VIA VIIA * * *

38 Periods Elements in the same period have the same number of layers of electrons * 7 * *

39 KNOW THE NAMES OF THE GROUPS/FAMILIES ON THE PERIODIC TABLE

40 Chemical Families * * *

41 KNOW WHAT AN ION IS AND HOW TO DETERMINE THE CHARGE OF AN ION

42 Ion: Atom (or molecule) that has a different number of electrons than protons, resulting in an overall positive or negative charge. negative positive

43 Example I: 9 F Fluorine Atom Fluoride Ion # protons = # electrons = 9 9 # protons = # electrons = 9 10 F gains 1 e Overall negative charge

44 Example II: 8 O Oxygen Atom Oxide Ion # protons = # electrons = 8 8 # protons = # electrons = 8 10 O gains 2 e Overall negative charge

45 Example III: 15 P Phosphorus Atom # protons = # electrons = Phosphide Ion gains 3 e # protons = # electrons = P 3-

46 Example IV: 19 K Potassium Atom # protons = # electrons = Potassium Ion 19 # protons = loses e # electrons = 18 K + Overall positive charge

47 Example V: 12 Mg Magnesium Atom # protons = # electrons = loses 2 e Magnesium Ion 12 # protons = # electrons = 10 Mg 2+

48 Ex VI: Chlorine gains 1e Ex VII: Ex VIII: Ex IX: Ex X: Aluminium Tin Copper Francium loses 3e gains 4e loses 2e Cl - Al 3+ Sn 4- Cu 2+ loses 1e Fr +

49 When an atom turns into an ion, it is by a transfer of electrons (to or from the outside layer); NOT a transfer of protons.

50 When an atom turns into an ion, it is by a transfer of electrons (to or from the outside layer); NOT a transfer of protons. Add 2 e Po Po 2- Remove 2 e Po Po 2+

51 If you add 1 electron to a platinum (Pt) atom, it becomes Pt True or False?

52 True or False? If you add 1 proton to a platinum (Pt) atom, it becomes Pt + If you could manage to add 1 proton to a platinum atom, it would no longer be the element platinum You will have turned it into gold

53 Sodium Atom I lost an electron. Sodium Ion You sure? I m positive.

54 BE ABLE TO BALANCE CHEMICAL EQUATIONS Skeleton Equation Al + F 2 AlF 3 Balanced Equation Al + F 2 AlF 3

55 Example 1: Caesium + Nitrogen. BALANCING CHEMICAL REACTIONS

56 Example 1: Caesium + Nitrogen. BALANCING CHEMICAL REACTIONS

57 KNOW THE DEFINITION OF AN ELECTROLYTE AND KNOW THE 3 TYPES OF ELECTROLYTES (ACIDS, BASES, SALTS)

58 When certain molecules are dissolved in water, they split up into ions.

59 When certain molecules are dissolved in water, they split up into ions. + _ + _ + _

60 When certain molecules are dissolved in water, they split up into ions. + _ + _ + _

61 When certain molecules are dissolved in water, they split up into ions. _ + _ This is called dissociation. + _ +

62 The ions can move around in the water, and they carry an electric charge. _ + _ + _ +

63 The ions can move around in the water, and they carry an electric charge. Because of this the resulting solution can now _ + _ conduct electricity. + _ +

64 The ions can move around in the water, and they carry an electric charge. Because of this the resulting solution can now _ + _ conduct electricity. + _ +

65 A substance that dissociates into ions when dissolved in water is called an electrolyte. _ + _ + _ +

66 A solution that conducts electricity due to the presence of ions is called an electrolytic solution. _ + _ + _ +

67 There are three types of electrolytic solutions. Acids Bases Salts _ + _ + _ +

68 KNOW THAT ACIDS RELEASE H + IONS, AND THAT BASES RELEASE OH - IONS

69 Example: Hydrogen chloride An acid is a substance that releases hydrogen ions, H +, in solution. HCl

70 An acid is a substance that releases hydrogen ions, H +, in solution. Example: Hydrogen chloride HCl HCl HCl

71 Example: Hydrogen chloride An acid is a substance that releases hydrogen ions, H +, in solution. HCl + H + Cl _ Acids are electrolytic; they will conduct electricity when dissolved in water. + HCl _ HCl + _

72 Example: Sodium hydroxide NaOH A base is a substance that releases hydroxide ions, OH -, in solution.

73 An base is a substance that releases hydroxide ions, OH -, in solution. Example: Sodium hydroxide NaOH NaOH NaOH

74 Example: Sodium hydroxide An base is a substance that releases hydroxide ions, OH -, in solution. NaOH + Na + OH _ Bases are electrolytic; they will conduct electricity when dissolved in water. NaOH _ + + NaOH _

75 BE ABLE TO RECOGNIZE ACIDS, BASES, AND SALTS BY THEIR CHEMICAL FORMULA

76 Molecular formulas The molecular formula of an acid will appear in one of the following two ways: Start with H HCl HF End with COOH CH 3 COOH C 5 H 7 O 5 COOH HNO 3 H 2 SO 4 Starts with H, but not an acid: H 2 O

77 Bases are also known as alkaline solutions The molecular formula of a base: Metal + OH NaOH KOH Ca(OH) 2 Exception (doesn t start with a metal): NH 4 OH Mg(OH) 2

78 The molecular formula of a salt: Metal + Non-metal(s) NaF CaCl 2 KNO 3 Exception (doesn t start with a metal): Can also start with NH 4 Al 2 (SO 4 ) 3

79 KNOW HOW EACH ELECTROLYTE REACTS TO LITMUS, METALS AND ELECTRICAL CONDUCTIVITY KNOW HOW TO READ THE PH SCALE (LESS THAN 7 = ACID, 7=NEUTRAL, GREATER THAN 7 = BASE)

80 Reaction with litmus paper: Cl _ H + H Cl + _

81 Reaction with litmus paper: ph of an acid is less than 7 Red litmus stays red Blue litmus turns red Cl _ H + H Cl + _ REACTS WITH METAL TO PRODUCE HYDROGEN GAS H 2!!!

82 Reaction with litmus paper: OH _ + Na OH Na + _

83 Reaction with litmus paper: Red litmus turns blue ph of a base is greater than 7 Blue litmus stays blue OH _ + Na OH Na + _

84 Reaction with litmus paper: Na + Cl _ Cl _ Na +

85 Reaction with litmus paper: ph of a salt is 7 (neutral) (note: there are exceptions) Red litmus stays red Blue litmus stays blue Na + Cl _ Cl _ Na +

86 BE ABLE TO CALCULATE HOW MUCH STRONGER ONE SUBSTANCE IS COMPARED TO ANOTHER BASED ON THE PH SCALE (X10 FOR EVERY JUMP) ph 7 ph 3 = 4 steps therefore 4 zeros ph 3 is x10,000 more acidic than ph 7

87 KNOW WHAT AN ACID-BASE INDICATOR IS

88 KNOW HOW TO READ THE INDICATOR CHARTS IF THE COLOUR OF UNIVERSAL INDICATOR IS GREEN, THE SUBSTANCE IS A NEUTRAL SUBSTANCE. ph =7

89 BE ABLE TO RECOGNIZE AND COMPLETE NEUTRALIZATION REACTIONS (ACID + BASE WATER + SALT)

90 Example I: Acid HCl + Base + NaOH Remember: when an acid or a base is dissolved in water it undergoes dissociation (splits into its ions)

91 Example I: Acid + Base Water + Salt HCl + NaOH H 2 O + NaCl Neutral

92 Example II: Acid HBr + Base + LiOH

93 Example II: Acid + Base Water + Salt HBr + LiOH H 2 O + LiBr

94 KNOW WHAT CONCENTRATION, SOLUTION, SOLUTE, SOLVENT, MASS AND VOLUME ARE Mass is usually the amount of solute you put into the solvent Volume is the amount of water, H 2 O Mass is the amount of solute you place into the solvent.

95 BE ABLE TO CALCULATE THE CONCENTRATION OF A GIVEN SOLUTION IN G/L, % AND PPM Grams per Litre % m/v ppm or mg/ L Formula Units C = grams / Litre m = grams (g) V = Litre (L) C = grams per 100 ml m = grams (g) V = millilitres (ml) C = mg per Litre m = milligrams (mg) V = Litre (L)

96 BE ABLE TO CONVERT BETWEEN ML AND L

97 CONVERTING UNITS x1000 x1000 kg g mg

98 CONVERTING UNITS x1000 x1000 kl L ml

99 THE FIRE TRIANGLE (ILLUSTRATES THE 3 CONDITIONS REQUIRED FOR COMBUSTION TO OCCUR) Combustion: An oxidation reaction that releases a large amount of energy.

100 CELLULAR RESPIRATION Glucose and oxygen react and generate energy. C 6 H 12 O O 2 6 CO H 2 O + Energy

101 PHOTOSYNTHESIS Reverse NOITSUBMOC Carbon dioxide and water react with sunlight to form oxygen and glucose (i.e. Maple syrup) 6 CO H 2 O + Energy C 6 H 12 O O 2

102

103 Electric Charge There are 2 types of electric charge

104 Electric Charge There are 2 types of electric charge Opposite charges attract Same charges repel

105

106 Static Charge by Friction Objects (like the atoms that make them up) are normally neutral. A piece of vinyl and a wool cloth are both made of atoms. Vinyl Wool

107 Static Charge by Friction Normally neutral, they each contain an equal number of positive and negative charges. Vinyl Wool

108 Static Charge by Friction When rubbed together (friction), many electrons are transferred from the wool onto the vinyl. Vinyl Wool

109 Static Charge by Friction When rubbed together (friction), many electrons are transferred from the wool onto the vinyl. Vinyl Wool

110 Static Charge by Friction When rubbed together (friction), many electrons are transferred from the wool onto the vinyl. Vinyl Wool

111 Static Charge by Friction How do we know which material gets the electrons? We look it up on a list The

112 Static Charge by Friction The material closer to the will gain electrons (become negatively charged)

113 Static Charge by Friction Example I: Vinyl & Wool

114 Static Charge by Friction Example I: Vinyl & Wool Example II: Glass & Wool

115 Static Charge by Friction Example I: Vinyl & Wool Example II: Glass & Wool Example III: Rubber & Fluororesin

116 Rubber Hair

117 Same charges repel

118 Static Charge by Conduction Neutral Object Charged Object Charged object touches a neutral object

119 Static Charge by Conduction Neutral Object Charged Object

120 Static Charge by Conduction Neutral Object Charged Object Electrons travel from one object into the other

121 Static Charge by Conduction Now, also Charged Charged Object Both objects now have the same charge

122

123 Static Charge by Induction Neutral Object Charged Object Charged object brought near a neutral object

124 Static Charge by Induction Neutral Object Charged Object Charged object brought near a neutral object

125 Static Charge by Induction Neutral Object Charged Object Charged object brought near a neutral object Charges shift within the neutral object (Sides temporarily charged)

126

127

128 Water When a water molecule is formed, the oxygen atom has a strong pull on the electrons from the hydrogen atoms. The oxygen has a negative charge. The hydrogens have a positive charge.

129 Water molecules falling

130 Method of static charging Materials at start Procedure Materials after Friction Both neutral Rub materials together 1 positively, 1 negatively charged Conduction 1 charged, 1 neutral Materials touch each other Both charged (same charge) Induction 1 charged, 1 neutral Materials near each other Sides temporarily charged on neutral object

131

132 Electric Circuit Closed path along which electrons from a power source can flow. Light Circuit diagram Graphical representation of an electric circuit. L1 Resistor V s R1 Switch SW1

133 Electric Circuit Circuit diagram

134 Example I: Analyzing a Circuit L1 V s SW1 OPEN OFF OFF L2 CLOSED ON ON

135 Example I: Analyzing a Circuit L1 V s SW1 OPEN OFF OFF L2 CLOSED ON ON

136 Example I: Too easy! L1 Analyzing a Circuit Yeah, give us a harder example! V s SW1 OPEN OFF OFF L2 CLOSED ON ON

137 Example II: very funny...

138 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

139 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

140 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

141 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

142 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

143 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

144 Example II: Analyzing a Circuit L1 L2 SW1 OPEN OPEN OFF OFF OPEN CLOSED OFF ON SW2 CLOSED OPEN OFF OFF CLOSED CLOSED ON ON V s

145

146 Dynamic Electricity Conductance / Resistance / Factors

147 Conductance: A measure of the ability to carry electric charge.

148

149

150 Resistance: A measure of the opposition to the flow of electricity. Symbol for Resistance (used in formulas): R Unit (resistance is measured in ): Ohms ; Greek letter Omega

151 Example: Measure Value Unit Resistance equal to 270 ohms Same idea as: Measure Value Unit

152 A Resistor (in an electric circuit) is a component that limits the flow of electric charge (electrons). Schematic symbol for a resistor: Resistors:

153 The higher the resistance value, the less electric current there is flowing through the circuit. Lower Resistor Value Higher Resistor Value

154 The higher the resistance value, the less electric current there is flowing through the circuit. Lower Resistor Value Higher Resistor Value

155 1) Material: Some materials conduct electricity better than others. 2) 3) Length: Diameter: (Less distance for electrons to travel) (More room for electrons to travel through) 4) Temperature: (Atoms more structured; less random motion)

156

157 Voltage V vs I Current

158 Math Class Electricity y V y = a x V = R I x I

159 Mathematical relation between Voltage, Resistance and Current Ohm s Law V = R I in Volts (V) Alessandro Volta Georg Ohm André-Marie Ampère

160 Example I: What current will travel through a component that has a resistance of 60 W if it is connected to a 12 V battery? I =? R = 60 W V = 12 V V = R I 12 = 60 I I = 0.2 A

161 Example II: What reading should appear on the voltmeter in the circuit below? A 20 W V

162 Example II: What reading should appear on the voltmeter in the circuit below? I = 70 ma A 20 W V

163 Example II: What reading should appear on the voltmeter in the circuit below? I = 70 ma A V =? R = 20 W I = 70 ma = 0.07 A 20 W V V = R I V = ( 20 )( 0.07 ) V = 1.4 V

164 The human body has an electrical resistance of about 10 kw. (it actually can vary from 1 kw 100 kw) Refer to the given chart to determine the (usual) effect of touching an uninsulated wire from a 120 V outlet. Example III: I (ma) Effect on a person Tingling sensations 3-10 Muscle contractions and pain Let-go threshold Respiratory paralysis Ventricular fibrillation (Death) Heart clamps tight Tissues and organs burn

165 Example III: The human body has an electrical resistance of about 10 kw. (it actually can vary from 1 kw 100 kw) Refer to the given chart to determine the (usual) effect of touching an uninsulated wire from a 120 V outlet. I (ma) Effect on a person Tingling sensations 3-10 Muscle contractions and pain Let-go threshold Respiratory paralysis Ventricular fibrillation (Death) Heart clamps tight Tissues and organs burn R = 10 kw = W V = 120 V I =? V = R I 120 = I I = A I = 12 ma

166 ELECTRICAL POWER & ENERGY James Watt James Prescott Joule

167 Power (P): A measure of the rate of transfer of energy. Power is measured in watts ( W ) P = V I Power ( W ) Potential Difference ( V ) Current ( A ) James Watt

168 Example I: What current will be drawn by an 85 W Fender Twin Reverb amplifier if it is connected to a 120 V outlet? I =? P = 85 W V = 120 V P = V I 85 = 120 I I = 0.71 A

169 Example II: How much power will be dissipated by a 20 W resistor that is connected to a potential difference of 6 V? P =? R = 20 W V = 6 V We need to know the current to find the power P = V I Georg Ohm Use my formula André Ampère

170 Example II: How much power will be dissipated by a 20 W resistor that is connected to a potential difference of 6 V? P =? R = 85 W V = 6 V V = R I We need to know the current to find the power P = V I Georg Ohm Use my formula André Ampère

171 Example II: How much power will be dissipated by a 20 W resistor that is connected to a potential difference of 6 V? P =? R = 20 W V = 6 V V = R I 6 = 20 I I = 0.3 A P = V I P = ( 6 ) ( 0.3 ) P = 1.8 W

172 Energy (E): A measure of the ability to do work. Energy is usually measured in joules ( J ) E = P t Energy ( J ) Power ( W ) time ( s ) James Prescott Joule

173 Example III: How much energy (in joules) is used by a 2 kw heater if it is operated at full power for 12 minutes? E =? P = 2 kw t = 12 min = 2000 W = 720 s E = P t E = ( 2000 ) ( 720 ) E = J

174 Unfortunately, energy is not just measured in joules. When measuring electrical energy consumption for an electricity bill, energy is measured in kilowatt-hours ( kwh ) Uh, oh E = P t ( kwh ) ( kw ) ( h )

175 Example IV: How much energy (in kilowatt-hours) is used by a 2 kw heater if it is operated at full power for 12 minutes? E =? P = 2 kw E = P t t = 12 min = 0.2 h E = ( 2 ) ( 0.2 ) E = 0.4 kwh

176 And that s not all E = P t Oh, no (Wh) ( W ) ( h )

177 Magnetic Field: Region around a magnet (or electric current) within which other magnetic objects will be affected.

178 How can we picture a magnetic field? A magnetic field is described (illustrated) by a series of lines (called magnetic field lines) that show how a North pole would be affected within that region.

179 In what direction would a North pole be pushed/pulled if it were near the following bar magnet? N N N N N N N N N S N N N N N N N N N N

180 The magnetic field is illustrated with a few lines that show the pattern, N N N N N N N N N S N N N N N N N N N N

181 The magnetic field is illustrated with a few lines that show the pattern, with arrowheads to show the direction of the magnetic push. S N

182 How can we see this pattern in the lab? S N

183 How can we see this pattern in the lab? Did someone say Iron man? S With Iron filings No, you Iron filings! fool. N

184 How can we see this pattern in the lab? Did someone say Iron man? With Iron filings No, you Iron fool. filings! Oh!

185 The iron filings become magnetized, then act like tiny compasses that line up in the magnetic field.

186 Iron filings over a bar magnet.

187 Look at the pattern, then draw a few lines (6 12) to show the basic shape S N

188 Complete the drawing by giving each line a direction. The direction can be determined by placing a compass in the magnetic field. S N

189 Complete the drawing by giving each line a direction. The direction can be determined by placing a compass in the magnetic field. S N

190 Complete the drawing by giving each line a direction. The direction can be determined by placing a compass in the magnetic field. S N

191 Complete the drawing by giving each line a direction. The direction can be determined by placing a compass in the magnetic field. S N

192 MAGNETIC FIELD OF A STRAIGHT WIRE A straight wire with a current flowing through it has a circular magnetic field around it. The magnetic field is represented by circular lines around the wire

193 Magnetic Field of a Straight Wire

194 Left Hand Rule Using your LEFT hand, point your thumb towards the positive end of the wire (the direction of the electron flow). Your fingers wrap around the wire and the curl of your fingers show the direction of the magnetic field.

195 Compasses When a compass is placed in the magnetic field, the north end of the compass will point in the direction of the magnetic field.

196 ENERGY

197 ENERGY Energy is the ability to do work or effect change.

198 ENERGY Energy is the ability to do work or effect change. Energy exists in many different forms.

199 Energy carried by electrons in motion.

200 Sources of electrical energy Power plants Batteries Generators

201 Radiant energy from the Sun. Source of solar energy Sun

202 Energy carried by electromagnetic radiation. (Includes visible light, as well as solar energy)

203 Sources of radiant energy Light bulbs The Sun Cellphones Microwave ovens

204 Energy resulting from the random motion of molecules in a substance.

205 Sources of thermal energy Fire Heating elements

206 Energy stored in molecular bonds.

207 Sources of chemical energy Fossil fuels Food

208

209 Energy stored in atomic nuclei.

210 Energy stored in atomic nuclei.

211 Source of nuclear energy Atomic nuclei

212 Source of nuclear energy Atomic nuclei

213 Energy from the movement of air. Source of wind energy Wind

214 Energy from the movement of water. Sources of hydraulic energy Rivers Ocean tides

215 Energy carried by sound waves. Sources of sound energy Voice Speakers

216 Energy stored in an object due to its compression or extension. Sources of elastic energy Compressed springs Stretched elastics

217 Energy stored in an object due to its compression or extension.

218 Energy can be neither created nor destroyed. Energy can be transmitted (from one place to another). Energy can be transformed (from one form into another). The total energy does not change.

219 Ex 1 (Energy can be transmitted from one place to another)

220 (Energy can be transmitted from one place to another) Ex 1 Electrical energy is transmitted (through wires) from a power station to a house. Electrical energy Electrical energy

221 (Energy can be transmitted from one place to another) Ex 2 Solar energy (or radiant energy) is transmitted (through space) from the Sun to a tree.

222 Ex 1 A toaster: (Energy can be transformed from one form into another) Electrical energy is transformed into energy. thermal

223 Ex 2 Photosynthesis: (Energy can be transformed from one form into another) Solar (or radiant) energy is transformed into chemical energy. Glucose

224 Ex 3 A wind turbine: (Energy can be transformed from one form into another) Wind energy is transformed into electrical energy.

225

226 ON OFF

227 Light bulbs transform electrical energy into radiant (light) energy. However, most of the electrical energy doesn t actually end up as light; most of the electrical energy is actually converted into thermal (heat) energy. With an incandescent light bulb, less than 5% of the electrical energy ends up as visible light. Efficiency ON OFF

228 Energy efficiency gives the percentage of energy consumed by a device that is actually transformed into what is called useful energy. ON OFF

229 Example 1: A compact fluorescent light bulb (CFL bulb) is more efficient than an incandescent or a halogen light bulb. Still, not great. A 13 watt CFL bulb operating for 10 hours consumes joules of electrical energy. In this time the bulb gives off joules of radiant (light) energy. Determine the efficiency of this CFL light bulb.

230 Example 2: Car motors are not very efficient. Only about 12% of the chemical energy in gasoline (consumed energy) actually turns the wheels to make the car move (useful energy). How much chemical energy is consumed by a car in order to provide J of energy to turn the wheels and make the car move?

231 Example 3: An electric kettle uses 1600 watts of power for 5 min. in order to boil 1 L of water; J of thermal energy was absorbed by the water in this time. Calculate the energy efficiency of this kettle. (thermal energy to boil the water) (We need to know how much energy the kettle used)

232 Example 3: An electric kettle uses 1600 watts of power for 5 min. in order to boil 1 L of water; J of thermal energy was absorbed by the water in this time. Calculate the energy efficiency of this kettle.

233