BBT CRASH COURSE MR. C. TAM

Transcription

1 BBT CRASH COURSE MR. C. TAM

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

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

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

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

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

16 Chemical Families * * *

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

18 Ion: Atom (or molecule) that has a different number of electrons than protons, resulting in an overall positive or negative charge. If an atom contains more electrons e than protons p +, it will have an overall charge that is negative If an atom contains more protons p + than electrons e, it will have an overall charge that is positive

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

20 Example 1: Caesium + Nitrogen. BALANCING CHEMICAL REACTIONS When caesium, Cs, reacts with nitrogen gas, N 2, a compound called caesium nitride, Cs 3 N is produced. Cs + N 2 Cs 3 N

21 Example 1: Caesium + Nitrogen. BALANCING CHEMICAL REACTIONS When caesium, Cs, reacts with nitrogen gas, N 2, a compound called caesium nitride, Cs 3 N is produced. Cs + N 2 Cs 3 N

22 BE ABLE TO DRAW BOHR-RUTHERFORD DIAGRAMS

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

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

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

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

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

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

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

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

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

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

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

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

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

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

37 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 + _

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

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

40 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 _

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

42 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

43 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

44 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

45 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)

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

47 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!!!

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

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

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

51 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 +

52 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

53 KNOW WHAT AN ACID-BASE INDICATOR IS

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

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

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

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

58 Example II: Acid HBr + Base + LiOH

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

60 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.

61 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 C = m V C = m V C = m V 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)

62 BE ABLE TO CONVERT BETWEEN ML AND L

63 CONVERTING UNITS x1000 x1000 kg g mg

64 CONVERTING UNITS x1000 x1000 kl L ml

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

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

67 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

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69 Electric Charge There are 2 types of electric charge Positive (+) and Negative ( )

70 Electric Charge There are 2 types of electric charge Positive (+) and Negative ( ) Opposite charges attract Same charges repel + + +

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72 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

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

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

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

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

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

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

79 Static Charge by Friction Example I: Vinyl & Wool

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

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

82 Rubber Hair

83 Same charges repel

84 Static Charge by Conductio n Charged Object Neutral Object Charged object touches a neutral object

85 Static Charge by Conductio n Charged Object Neutral Object

86 Static Charge by Conductio n Charged Object Neutral Object Electrons travel from one object into the other

87 Static Charge by Conductio n Charged Object Now, also Charged Both objects now have the same charge

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

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

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

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94 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.

95 Water molecules falling

96 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

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98 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

99 Electric Circuit Circuit diagram

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

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

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

103 Example II: very funny...

104 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

105 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

106 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

107 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

108 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

109 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

110 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

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112 Dynamic Electricity Conductance / Resistance / Factors

113 Conductance: A measure of the ability to carry electric charge. High conductance Goodconductor Easy for electricity to travel through Low conductance Poor conductor

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116 Resistance: A measure of the opposition to the flow of electricity. High resistance Poorconductor Hard for electricity to travel through Low resistance Good conductor Symbol for Resistance (used in formulas): Unit (resistance is measured in ): R Ohms ; Symbol: Ω Greek letter Omega

117 Example: Measure Value Unit R = 270 Ω Resistance equal to 270 ohms Same idea as: V = 750 ml Measure Value Unit

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

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

120 The higher the resistance value, the less electric current there is flowing through the circuit. Lower resistance more current brighter light. Lower Resistor Value Higher Resistor Value

121 1) 2) 3) Material: Length: Diameter: Some materials conduct electricity better than others. Copper Very good conductor Low electrical resistance Shorter wire Better conductor Lower resistance (Less distance for electrons to travel) Larger diameter Better conductor Lower resistance (More room for electrons to travel through) 4) Temperature: Lower temperature Better conductor Lower resistance (Atoms more structured; less random motion)

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123 Voltage V vs I Current

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

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

126 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

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

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

129 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

130 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

131 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

132 ELECTRICAL POWER & ENERGY James Watt James Prescott Joule

133 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

134 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

135 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

136 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

137 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

138 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

139 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

140 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 )

141 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

142 And that s not all Energy can even be measured in watt-hours ( W h ) E = P t Oh, no ( W h ) ( W ) ( h )

143 ENERGY

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

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

146 Energy carried by electrons in motion.

147 Sources of electrical energy Power plants Batteries Generators

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

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

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

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

152 Sources of thermal energy Fire Heating elements

153 Energy stored in molecular bonds.

154 Sources of chemical energy Fossil fuels Food

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156 Energy stored in atomic nuclei.

157 Energy stored in atomic nuclei.

158 Source of nuclear energy Atomic nuclei

159 Source of nuclear energy Atomic nuclei

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

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

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

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

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

165 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.

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

167 (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

168 (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.

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

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

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

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173 ON OFF

174 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

175 Energy efficiency gives the percentage of energy consumed by a device that is actually transformed into what is called useful energy. Energy Efficiency = Useful energy Total energy consumed 100% ON OFF

176 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. Efficiency = Useful energy Total energy consumed 100% J Efficiency = 100% J Efficiency = 8.5 %

177 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? Efficiency = 12% = 0.12 = Useful energy Total energy consumed 100% J E consumed 100% J E consumed 0.12 E consumed = J J E consumed = 0.12 Efficiency = J

178 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. Useful Energy = J (thermal energy to boil the water) Efficiency = Useful energy Total energy consumed 100% Electrical energy consumed by the kettle =? (We need to know how much energy the kettle used) E = P t

179 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. E = P t E = 1600 W 300 s E = J (consumed) Efficiency = Efficiency = Useful energy Total energy consumed 100 % J J 100 % Efficiency = 62.5 %

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