Transcript Slide 1

Voltage
Electrochemical Batteries
012-10740 r1.04
Electrochemical Batteries
Introduction
Journals and Snapshots
The Snapshot button is used to capture the
screen.
The Journal is where snapshots are stored
and viewed.
The Share button is used to export
or print your journal to turn in your
work.
Each page of this lab that
contains the symbol
should be inserted into your
journal. After completing a
lab page with the snapshot
symbol, tap
(in the upper
right hand corner) to insert
the page into your journal.
Note: You may want to take a
snapshot of the first page of
this lab as a cover page for
your Journal.
Electrochemical Batteries
Lab Challenges
• Determine the components required to make a battery.
• List metals in order by the amount of voltage (energy per unit charge) they
produce when used in a battery.
Devices need energy to operate
Energy from the
burning of gasoline.
Energy from the electricity that
runs through the wires and
outlets in your house.
Energy from batteries.
Electrochemical Batteries
Background
• There are many types of energy. Energy can be classified as either kinetic
energy or potential energy.
• Kinetic energy is energy in motion, while potential energy is energy that is
stored (in various ways) until being released as kinetic energy.
Electrochemical Batteries
...Background
• Electricity has kinetic energy because it is the flow of
electrons from one substance to another.
Copper wire
• A battery has potential energy because it stores chemicals
which contain energy in their bonds (chemical energy).
• When the chemicals are allowed to react, electrons are
transferred producing energy in the form of electricity.
Electrochemical Batteries
Self-Check
1. Electricity is a form of _______________.
a) static discharge
b) potential energy
c) combustion energy
d) kinetic energy
Electrochemical Batteries
...Background
• Chemicals react in order to form new bonds that are lower in energy and thus
more stable. Chemicals are the most stable when their valence electron shell is
full.
Na
Sodium atom
Na+
+é
Sodium ion
• Metallic atoms can lower their potential energy and become more stable by
losing electrons to fill their outermost energy shell.
• The easier a metal loses its electrons the more reactive the metal is and the
more energy it can produce.
Electrochemical Batteries
Self-Check
2. What makes an atom stable?
a) a full valence shell
b) an equal number of protons and electrons
c) an unequal number of protons and electrons
d) losing electrons
+é
Electrochemical Batteries
...Background
• An electrochemical battery (voltaic cell) is
designed to take advantage of the relative
abilities of metals to lose electrons.
• Two metals (electrodes) are physically
separated from each other and are
connected by a wire conductor.
• Each metal is surrounded by an electrolyte
solution and the solutions are connected
using a salt bridge which allows ions to
flow between cells in order to balance the
charges and complete the circuit.
Wire
Metal #1
Metal #2
Salt
bridge
Electrolyte solutions
Electrochemical Batteries
...Background
• An equilibrium (balance) between the metal
and its ion is established at each electrode
depending on the ease with which the metal
loses its electrons (a half-reaction).
• The greater the difference between the two
metals' ability to lose electrons, the greater
the difference in negative charge created
between the two electrodes. This difference
(potential difference) is measured as voltage
(energy per unit charge). The greater the
difference between the two metals the more
energy per charge the battery can produce.
Half-reaction
(more active metal)
Half-reaction
(less active metal)
Electrochemical Batteries
Self-Check
3. What is voltage a measure of?
a) flow of electrons
b) energy per unit charge
c) losing electrons
d) reaction time
Electrochemical Batteries
...Background
• When the battery is switched on, the
electrons move from the more active metal
through the wire to the less active metal
allowing the two half-reactions to occur
simultaneously to produce energy.
• The more active metal loses electrons
(oxidation) while the less active metal gains
electrons (reduction). This type of chemical
reaction is called a redox reaction.
Losing electrons
Gaining electrons
Electrochemical Batteries
...Background
• On a battery, the two electrodes are
differentiated from each other by marking
one with a "+" the other with a "-".
• The metals and electrolytes used in a
battery determine the voltage produced
by the battery. Each different chemical
reaction has a characteristic voltage.
9V Battery
1.5V Battery
Electrochemical Batteries
Safety
• Follow all common laboratory safety
procedures.
• Beware of sharp edges on the metal
electrodes.
• Do not eat any of the food used in this lab.
Discard the fruit according to your teacher’s
instructions.
• Wash your hands after handling chemicals,
electrodes, equipment, and glassware.
Electrochemical Batteries
Materials and Equipment
Collect all of these materials before beginning the lab.
• Voltage sensor
• Alligator clips, (1 black, 1 red)
• Beakers (2), 50-mL
• Graduated cylinder, 50-mL
• Thick string or yarn, 20 cm
• Wash bottle and waste container
• Knife to cut fruit
waste
Electrochemical Batteries
...Materials and Equipment
Also collect these additional materials before starting.
• Copper strip
• Zinc strip
• Magnesium strip
• Two or more of the following metal strips:
lead, iron, nickel, or tin
• 0.1 M Sodium chloride solution, 5-10 mL
• 0.1 M Hydrochloric acid, 50 mL
• Lemon
• Tomato
Na-Cl
Electrochemical Batteries
Sequencing Challenge
A. Test the voltage of
zinc, then replace
zinc with three
different metals and
test the voltage.
B. Replace the HCl
with a lemon and
then a tomato and
find the voltage
produced by each
metal.
C. Assemble the
electrochemical
battery using 0.1M
HCl as the electrolyte
and copper and zinc
as the electrodes.
D. Use the data
collected to list the
metals in order by
the amount of
voltage they
produced when used
in a battery.
The steps to the left are part of
the procedure for this lab
activity. They are not in the
right order. Determine the
correct sequence of the steps,
then take a snapshot of this
page.
Electrochemical Batteries
Setup: 0.1 M HCl
1. Connect the voltage probe directly to the data
collection system.
2. Connect the red alligator clip to the red voltage
probe lead and connect the black alligator clip to
the black voltage probe lead.
3. Pour approximately 25 mL of 0.1 M hydrochloric
acid (HCl) into each 50-mL beaker. The HCl is the
electrolyte solution.
4. Place a zinc strip in one beaker and a copper strip
in the other.
Note: Copper will be used in all the electrochemical cells as a
reference to compare the other metals.
Q1: What is an electrolyte
solution? What makes
this solution
electrolytic?
Electrochemical Batteries
Setup: 0.1 M HCl
5. Wet a 20 cm piece of string with the 0.1 M sodium
chloride solution and hang it between the two
beakers with the ends submerged in the
electrolyte solution. This is the salt bridge.
Q2: Is it necessary to have a
separate beaker for the
copper strip and the zinc
strip? Explain.
Electrochemical Batteries
Setup: 0.1 M HCl
6. Enter the names of all the
metals you will use with
copper to create your
electrochemical batteries.
Start by entering "zinc" in
row one (do not list copper)*
*To Enter Data into a Table:
1. Tap
to open the tool
palette.
2. Tap
then tap a cell in the
data table to highlight it in
yellow.
3. Tap
to open the
Keyboard screen.
Electrochemical Batteries
Collect Data: HCl
1. Tap
to start a data set.
2. Attach the red lead to the
copper strip and the black
lead to zinc strip using the
alligator clips.
3. Tap
to record the
voltage (run 1: HCl).
4. Replace the zinc strip with
the next metal in your table.
Tap
to record the
voltage.
5. Repeat step 4 until the
voltage of each metal has
been recorded.
6. Tap
to stop the data set.
Electrochemical Batteries
Collect Data: HCl
Q3: What was the dependent variable and the independent variable in the
experiment performed on the previous page?
Electrochemical Batteries
Setup: Lemon
1. Remove both metal strips from the beakers.
2. Clean all the metal strips with water and dry
them.
3. Roll the lemon firmly on the tabletop with the
palm of your hand. Use a knife to make two slits
wide enough for the electrodes to be inserted
about 2-3 cm apart from each
other in the lemon.
4. Insert the copper strip
in one slit and the zinc
strip in the other slit.
Q4: Is there an electrolyte
solution in the lemon?
Explain.
Electrochemical Batteries
Collect Data: Lemon
1. Tap
to start a data set.
This data set will be recorded
in the 2nd voltage column.
2. Attach the red lead to the
copper strip and the black
lead to zinc strip using the
alligator clips.
3. Tap
to record the voltage
(run 2: lemon).
4. Replace the zinc strip with
the next metal in the table.
Tap
to record the voltage.
5. Repeat step 4 until the
voltage of each metal has
been recorded.
6. Tap
to stop the data set.
Electrochemical Batteries
Setup: Tomato
1. Remove both metal strips from the lemon.
2. Clean all the metal strips with water and dry
them.
3. Use a knife to make two slits wide enough for the
electrodes to be inserted about 2-3 cm apart
from each other in the tomato.
4. Insert the copper strip in one slit and the zinc
strip in the other slit.
Q5: What is voltage a
measure of?
Electrochemical Batteries
Collect Data: Tomato
1. Tap
to start a data set. This
data set will be recorded in
the third voltage column.
2. Attach the red lead to the
copper strip and the black
lead to zinc strip using the
alligator clips.
3. Tap
to record the voltage
(run 3: tomato).
4. Replace the zinc strip with the
next metal in the table. Tap
to record the voltage.
5. Repeat step 4 until the voltage
of each metal has been
recorded.
6. Tap
to stop the data set.
Electrochemical Batteries
Data Analysis
1. List metals in order by the
amount of voltage they
produce when used in a
battery with 0.1 M HCl
electrolyte solution (first
voltage column). Start with
the highest!
Electrochemical Batteries
2. List metals in order by the
amount of voltage they
produce when used in a
lemon battery (second
voltage column). Start with
the highest!
Electrochemical Batteries
3. List metals in order by the
amount of voltage they
produce when used in a
tomato battery (third
voltage column). Start with
the highest!
Electrochemical Batteries
Analysis
1. What components are necessary to make
a battery?
Electrochemical Batteries
Analysis
2. Did the type of electrochemical battery created
(HCl, lemon, or tomato) affect the ranking of the
metals?
Electrochemical Batteries
Analysis
3. What was the source of the electrons in the battery?
Electrochemical Batteries
Analysis
4. Which pair of electrodes would make the
most powerful battery? How do you know?
Electrochemical Batteries
Synthesis
1. Batteries come in all shapes, sizes, and voltages. Car batteries, cell phone
batteries, computer batteries, and flashlight batteries are all different from each
other. Explain how each of these batteries are similar and suggest a reason for
their different voltages.
Electrochemical Batteries
Synthesis
2. Why do you think batteries “go dead?”
Electrochemical Batteries
Synthesis
3. Why do you think many electronic
devices require more than one
battery?
Electrochemical Batteries
Multiple Choice
1. In an electrochemical battery, electricity is
generated by the flow of ___________.
a) fruit
b) metals
c) protons
d) electrons
Electrochemical Batteries
Multiple Choice
2. In a fruit battery, the fruit acts as ________.
a) a metal
b) electrons
c) an electrolyte solution
d) voltage
Electrochemical Batteries
Multiple Choice
3. Voltage is a measure of ______________.
a) the number of electrons
b) the difference between the desire for electrons
c) the time it takes for an electron to travel
through a circuit
d) the concentration of salt in fruit
12 V battery
Electrochemical Batteries
Multiple Choice
4. In the fruit battery, the electrons were generated
from _______________.
a) the metal electrode
b) the fruit
c) the wire
d) the electrolyte solution
Electrochemical Batteries
Multiple Choice
5. In an electrochemical battery, chemical energy is
converted to ___________.
a) potential energy
b) electricity
c) sound
d) light
Electrochemical Batteries
Congratulations!
You have completed the lab.
Please remember to follow your teacher's instructions for cleaning-up and submitting
your lab.
Electrochemical Batteries
References
All images were taken from PASCO documentation, public domain clip art, or Wikimedia Foundation Commons.
1. CARTOON CAR http://freeclipartnow.com/transportation/cars/car-ride.jpg.html
2. LAMP http://freeclipartnow.com/household/furniture/desk-lamp.jpg.html
3. OUTLET http://freeclipartnow.com/household/Electricaloutletandplug.jpg.html
4. CELL PHONE http://freeclipartnow.com/electronics-technology/phones/mobile-phones/cellphone-crisp-small.jpg.html
5. IPOD http://freeclipartnow.com/music/listening/ipod.jpg.html
6. BOWLING BALL http://freeclipartnow.com/recreation/sports/bowling/blowling-ball-01.jpg.html
7. BALANCED ROCK http://freeclipartnow.com/nature/scenery/Balanced-Rock-CO.jpg.html
8. RUNNING MAN http://freeclipartnow.com/recreation/sports/fitness/running-man.jpg.html
9. BATTERY http://freeclipartnow.com/science/energy/batteries/battery.jpg.html
10. LIGHT BULB http://freeclipartnow.com/household/lightning/Lightbulb3.jpg.html
11. CAUTION NO FOOD http://commons.wikimedia.org/wiki/File:D-P019_Essen_und_Trinken_verboten_ty.svg
12. CAUTION FROM BATTERIES http://commons.wikimedia.org/wiki/File:D-W020_Warnung_vor_Gefahren_durch_Batterien_ty.svg
13. KNIFE http://commons.wikimedia.org/wiki/File:Gemuesemesser.jpg
14. SODIUM CHLORIDE http://commons.wikimedia.org/wiki/File:Sodium-chloride-3D-ionic.png
15. LEMON http://freeclipartnow.com/food/fruits/lemons/lemon-simple.jpg.html
16. TOMATO http://freeclipartnow.com/d/19948-2/tomato-casual.jpg
17. BATTERY PILE http://commons.wikimedia.org/wiki/File:Versch._Batterien.JPG
18. REMOTE http://freeclipartnow.com/recreation/entertainment/television-remote-control.jpg.html
19. AA BATTERIES http://commons.wikimedia.org/wiki/File:Akku_AA_LR6_Mignon.jpg