1. Trace the carbon atom(s) from the calcium carbide through the experiment, showing the chemical reaction(s) that takes place in each step of the experiment. There should be two Place filter paper in funnel. Attach hose to vacuum 14 reactions where carbon dioxide escapes as a product and one reaction where carbon dioxide appears as a reactant.
4.* In the last step of this experiment, you treated calcium carbonate with dilute acid, causing the solid to fizz. Briefly describe what building or structural materials contain calcium carbonate and indicate what effects acid rain may have on these materials. Would you expect buildings or monuments made from carbonates to "fizz" when exposed to acid rain? Find examples of materials in your neighborhood that may have succumbed to acid rain, indicating what effects acid rain had on the material you are describing, and indicating the chemical reaction(s) that are taking place with that material upon exposure to acid rain.
EXPERIMENT 4 Chemical Reactions Involving Changes in States of Matter or Pieces of the Carbon Cycle INTRODUCTION There are 3 basic states of matter that we encounter in chemical reactions- solid, liquid and gas. In this laboratory exercise you will experiment with some chemical reactions that produce substances that may be familiar to you. Adding a substance to water to produce a flammable gas may seem remarkable, but this reaction was the sole source of acctylene prior to 1955, and was the source of valuable organic chemicals from 1940 to 1965. Caleium carbide was used to generate gas for lights in homes as well as vehicles (horse-drawn and horseless carriages) before electric lights became common. Carbide lamps can still be found in flea markets and antique fairs. The chemical reaction can be written as: CaC (s) 2HO) 6 CH (g) Ca(OH (aq) Acetylene is used commercially for welding and cutting steel and for glass blowing because it burns with a very hot flame when mixed with oxygen. The combustion of acetylene is written as 2 CH: (g)+50 (g) 6 4 CO, (g)2H,0 (g The calcium hydroxide, or lime water, produced in the first reaction combines with the carbon dioxide in your breath to produce insoluble calcium carbonate: Ca(OH)2 (aq) CO2 (g) 6 CaCOs (s) Ho (0) Acidifying the calcium carbonate causes it to fizz. The acid converts calcium carbonate to carbonic acid, releasing carbon dioxide into the atmosphere. This is the same reaction that occurs when marble or limestone (other forms of calcium carbonate) are exposed to acid rain. 1 Kirk-Othmer Encyclopedia of Chemical Technology, John Wiley and Sons: New York 1978; Vol. 4, pp 505-519.
