Part 2 – Comparing the reactivity of some metals with acids Manymetals react with acids, via an electron-transfer(oxidation-reduction) reaction that transforms the metal intodissolved metal ions. A co-product of this reaction is hydrogengas, formed when hydrogen ions in the acid solution take upelectrons from the metal and couple. Your task here is to test afew different metals to see how their reaction intensities compare.1. Obtain 12 clean small test tubes (they can be slightly wet).Divide them into three sets of four tubes, and label the sets as:“HCl”, “acetic acid” and “water”. 2. To the four “water” testtubes, add about 1 mL of water. To the four “HCl” test tubes, addabout 1 mL of 3 M hydrochloric acid using the 1 mL graduatedpipette that goes with the reagent bottle. To the four “aceticacid” tubes, add 1 ml of 3 M acetic acid. (Do not mix up thedroppers!) Carefully note the smells of the two acids. Do this bywafting air over the sample towards your nose with your hand -never smell a chemical directly. Exp.2: OBSERVATIONS 2 - 4 3. Nowdivide the tubes into four sets, one of each kind. Label them (orplace them on a labeled sheet of paper) as: “steel wool”, “Mg”, “Alsheet” and “Al foil”. 4. To each “steel wool” tube: add a smallloosely packed ball of steel wool about 3 mm in diameter. Makeinitial observations and note the time, then push the steel wooldown into the liquids with a clean glass stir rod. Record yourobservations immediately after mixing and again as time passes:colour changes, gas formation, solid formation (cloudiness),odours, and heat evolution all provide evidence of chemicalreaction. [Make notes on Observations/Data page.] Note: compare theacid-treated samples to the “control” water-treated sample – onlythen can you determine whether any chemical reactions observed arecaused by the acid or simply by the water also present. 5. Repeatstep 4 with the other metals: ~5 mm strip of magnesium ribbon, 5 mmsquare of aluminum sheet, and 5 mm diameter loose ball of aluminumkitchen foil.

Regarding Part 2: Consider the physical natureof the metals you tested, their positions on the periodic table,and the different strengths of the acids you used. What conclusionscan you draw from your observations of the action of the acids onthe different metals you tested? Be careful to explicitlydistinguish between speculations you cannot back up andspeculations based on any chemistry you may already havelearned.