Sources of images: The left side image is taken from- Tutors4you.com and right image is taken from- bouman.chem.georgetown.com 1 Study of Chemistry behind electroplating

1. Define two types of ions. 2. Differentiate between oxidation and reduction reactions. 3. What is the difference between a cathode and an anode? 4. How do electrolyte solutions conduct electricity? 5. What is mole? 6. How can you convert “grams” of a substance to “moles” of that substance?

1. Positive Ion: A neutral atom gets positive charge after losing electrons and it gets negative charge after gaining electrons. 2. Oxidation is loss of electrons and reduction is gain of electrons. You can remember it with this: LEO says GER. (L- losing, E- electrons, O- oxidation; G- gaining, E- electrons, R- reduction) 3. Cathode is the negative electrode, where reduction takes place and anode is the positive electrode where oxidation takes place.

4. Electrolyte solutions contain free ions which carry charges. For example salt water (NaCl) dissolved in water contains Na + and Cl - ions to conduct electricity. 5. Amount of pure substance containing same # of chemical units as there are atoms in exactly 12 grams of carbon (C-12). There are 6.02 × atoms in 12 grams of C Divide the given mass (in grams) with the molar mass of the substance.

 Mixture of Electricity and Chemistry  Coating the surfaces of the metals with other metals  For example – toasters, grills and fenders, camera cases and more products that you can name have special protective electroplated coatings.  Today we’ll use electrochemistry to coat pennies and nickels

 The salt solution has metal ions (M ++ ) and acid ions (A -- ). The battery has negative and positive electrodes  M ++ ions are attracted to the negative electrode which is cathode (opposite charges attract).They jump onto the electrode to form a metal coating  A -- ions are attracted towards the positive terminal which is anode. They attack the electrode and metal from it goes into the solution

1. Clean the pennies with a mixture of 3g NaCl and 15 mL vinegar; rinse and dry. 2. Mass the pennies and record the value in “grams”. Bend a paper clip as shown below: Picture source: 7

3. Line up the three pennies, and place the long leg of the bent paper clip across them, as shown in figure in next slide (If you want Lincoln's head plated, put the wire on the opposite side.) Use a 2-inch length of mounting tape or non-conducting tape to fasten the paper clip to the coins as shown in figure (in next slide).Be sure you press the tape tightly against the paper clip and coins, so the paper clip makes good contact with each coin (important for electrical purposes in the plating process), and the coins are securely held together as a "gang" of three coins that can be moved as a single unit.

 Picture of how to connect pennies described in step #4. Picture source: ng.pdf

4. Use one of the alligator clip leads to connect the negative end of the battery to the gang of pennies. Use the other lead to connect the positive end of the battery to the pointed end of the zinc-coated (galvanized) nail. Place the gang of pennies and the nail in the beaker, but be sure the pennies and the nail do not touch each other see figures in next slide. If necessary, use pieces of masking tape near the top of the beaker to hold things in place.

Picture source: ing.pdf