Voltage

1. Voltage Electrochemical Batteries 012-10740 r1.04

2. Electrochemical Batteries Introduction 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. 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. Note: You may want to take a snapshot of the first page of this lab as a cover page for your Journal.

3. 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 electricity that runs through the wires and outlets in your house. Energy from the burning of gasoline. Energy from batteries.

4. 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.

5. 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.

6. Electrochemical Batteries Self-Check • Electricity is a form of _______________. • static discharge • potential energy • combustion energy • kinetic energy

7. 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. + é Na Na+ Sodium atom 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.

8. Electrochemical Batteries Self-Check • What makes an atom stable? • a full valence shell • an equal number of protons and electrons • an unequal number of protons and electrons • losing electrons + é

9. Electrochemical Batteries ...Background Wire Metal #1 Metal #2 • 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. Salt bridge Electrolyte solutions

10. 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 (less active metal) Half-reaction (more active metal)

11. Electrochemical Batteries Self-Check • What is voltage a measure of? • flow of electrons • energy per unit charge • losing electrons • reaction time

12. 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

13. 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

14. 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.

15. 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

16. 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

17. Electrochemical Batteries Sequencing Challenge 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. 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.

18. Electrochemical Batteries Setup: 0.1 M HCl Q1: What is an electrolyte solution? What makes this solution electrolytic? • Connect the voltage probe directly to the data collection system. • Connect the red alligator clip to the red voltage probe lead and connect the black alligator clip to the black voltage probe lead. • Pour approximately 25 mL of 0.1 M hydrochloric acid (HCl) into each 50-mL beaker. The HCl is the electrolyte solution. • 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.

19. Electrochemical Batteries Setup: 0.1 M HCl Q2:Is it necessary to have a separate beaker for the copper strip and the zinc strip? Explain. • 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.

20. Electrochemical Batteries Setup: 0.1 M HCl • 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: • Tapto open the tool palette. • Tap then tap a cell in the data table to highlight it in yellow. • Tap to open the Keyboard screen.

21. Electrochemical Batteries Collect Data: HCl • Tap to start a data set. • Attach the red lead to the copper strip and the black lead to zinc strip using the alligator clips. • Tap to record the voltage (run 1: HCl). • Replace the zinc strip with the next metal in your table. Tap to record the voltage. • Repeat step 4 until the voltage of each metal has been recorded. • Tap to stop the data set.

22. Electrochemical Batteries Collect Data: HCl Q3:What was the dependent variable and the independent variable in the experiment performed on the previous page?

23. Electrochemical Batteries Setup: Lemon Q4: Is there an electrolyte solution in the lemon? Explain. • Remove both metal strips from the beakers. • Clean all the metal strips with water and dry them. • 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. • Insert the copper strip in one slit and the zinc strip in the other slit.

24. Electrochemical Batteries Collect Data: Lemon • Tap to start a data set. This data set will be recorded in the 2nd voltage column. • Attach the red lead to the copper strip and the black lead to zinc strip using the alligator clips. • Tap to record the voltage (run 2: lemon). • Replace the zinc strip with the next metal in the table. Tap to record the voltage. • Repeat step 4 until the voltage of each metal has been recorded. • Tap to stop the data set.

25. Electrochemical Batteries Setup: Tomato Q5: What is voltage a measure of? • Remove both metal strips from the lemon. • Clean all the metal strips with water and dry them. • 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. • Insert the copper strip in one slit and the zinc strip in the other slit.

26. Electrochemical Batteries Collect Data: Tomato • Tap to start a data set. This data set will be recorded in the third voltage column. • Attach the red lead to the copper strip and the black lead to zinc strip using the alligator clips. • Tap to record the voltage (run 3: tomato). • Replace the zinc strip with the next metal in the table. Tap to record the voltage. • Repeat step 4 until the voltage of each metal has been recorded. • Tap to stop the data set.

27. Electrochemical Batteries Data Analysis • 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!

28. Electrochemical Batteries • List metals in order by the amount of voltage they produce when used in a lemon battery (second voltage column). Start with the highest!

29. Electrochemical Batteries • List metals in order by the amount of voltage they produce when used in a tomato battery (third voltage column). Start with the highest!

30. Electrochemical Batteries Analysis • What components are necessary to make a battery?

31. Electrochemical Batteries Analysis • Did the type of electrochemical battery created (HCl, lemon, or tomato) affect the ranking of the metals?

32. Electrochemical Batteries Analysis • What was the source of the electrons in the battery?

33. Electrochemical Batteries Analysis • Which pair of electrodes would make the most powerful battery? How do you know?

34. Electrochemical Batteries Synthesis • 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.

35. Electrochemical Batteries Synthesis • Why do you think batteries “go dead?”

36. Electrochemical Batteries Synthesis • Why do you think many electronic devices require more than one battery?

37. Electrochemical Batteries Multiple Choice • In an electrochemical battery, electricity is generated by the flow of ___________. • fruit • metals • protons • electrons

38. Electrochemical Batteries Multiple Choice • In a fruit battery, the fruit acts as ________. • a metal • electrons • an electrolyte solution • voltage

39. Electrochemical Batteries Multiple Choice • Voltage is a measure of ______________. • the number of electrons • the difference between the desire for electrons • the time it takes for an electron to travel through a circuit • the concentration of salt in fruit 12 V battery

40. Electrochemical Batteries Multiple Choice • In the fruit battery, the electrons were generated from _______________. • the metal electrode • the fruit • the wire • the electrolyte solution

41. Electrochemical Batteries Multiple Choice • In an electrochemical battery, chemical energy is converted to ___________. • potential energy • electricity • sound • light

42. Electrochemical Batteries Congratulations! You have completed the lab. Please remember to follow your teacher's instructions for cleaning-up and submitting your lab.

43. Electrochemical Batteries References • All images were taken from PASCO documentation, public domain clip art, or Wikimedia Foundation Commons. • CARTOON CAR http://freeclipartnow.com/transportation/cars/car-ride.jpg.html • LAMP http://freeclipartnow.com/household/furniture/desk-lamp.jpg.html • OUTLET http://freeclipartnow.com/household/Electricaloutletandplug.jpg.html • CELL PHONE http://freeclipartnow.com/electronics-technology/phones/mobile-phones/cellphone-crisp-small.jpg.html • IPOD http://freeclipartnow.com/music/listening/ipod.jpg.html • BOWLING BALL http://freeclipartnow.com/recreation/sports/bowling/blowling-ball-01.jpg.html • BALANCED ROCK http://freeclipartnow.com/nature/scenery/Balanced-Rock-CO.jpg.html • RUNNING MAN http://freeclipartnow.com/recreation/sports/fitness/running-man.jpg.html • BATTERY http://freeclipartnow.com/science/energy/batteries/battery.jpg.html • LIGHT BULB http://freeclipartnow.com/household/lightning/Lightbulb3.jpg.html • CAUTION NO FOOD http://commons.wikimedia.org/wiki/File:D-P019_Essen_und_Trinken_verboten_ty.svg • CAUTION FROM BATTERIES http://commons.wikimedia.org/wiki/File:D-W020_Warnung_vor_Gefahren_durch_Batterien_ty.svg • KNIFE http://commons.wikimedia.org/wiki/File:Gemuesemesser.jpg • SODIUM CHLORIDE http://commons.wikimedia.org/wiki/File:Sodium-chloride-3D-ionic.png • LEMON http://freeclipartnow.com/food/fruits/lemons/lemon-simple.jpg.html • TOMATO http://freeclipartnow.com/d/19948-2/tomato-casual.jpg • BATTERY PILE http://commons.wikimedia.org/wiki/File:Versch._Batterien.JPG • REMOTE http://freeclipartnow.com/recreation/entertainment/television-remote-control.jpg.html • AA BATTERIES http://commons.wikimedia.org/wiki/File:Akku_AA_LR6_Mignon.jpg