sometimes a chemical is added to speed up a reaction

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Unformatted text preview: C8 H18 (l) + O2 (g) à CO2 (g) + H2 O (g) C: 8 on reactant side, 1 on product side H: 18 on reactant side; 2 on product side O: 2 on reactant side; 3 on product side (notice it is in both compounds on the product side) The same chemical equation balanced: 2 C8 H18 (l) + 25 O2 (g) à 16 CO2 (g) + 18 H2 O (g) C: 16 on reactant side, 16 on product side: balanced H: 36 on reactant side; 36 on product side: balanced O: 50 on reactant side; 50 on product side: balanced (Notice that in a balanced chemical equation, the stoichiometric coefficients are the smallest possible whole numbers that balance the equation; remember to take out any common denominators from your final answer and leave no fractions.) Sometimes a chemical is added to speed up a reaction. If these chemicals are not consumed in the reaction (that is to say, there is exactly as much of the chemical after the reaction as we had before the reaction), then the chemical is called a “catalyst”. For example, your car has a catalytic converter to speed up the reaction of carbon monoxide (a poisonous gas) and oxygen to form carbon dioxide (a less toxic gas). The catalyst is platinum; if the platinum were consumed in the reaction, we would periodically have to pay to have new platinum put into our cars; how much would you enjoy that? However, because the platinum is a catalyst, exactly the same amount of platinum is in your car today as when you first bought it. These chemicals either do not show up in the chemical equation at all, or they are placed above the arrow and are not balanced with the rest of the reaction. Dakota State University Page 62 of 232 Experiment 3: Chemical Reactions General Chemistry I and II Lab Manual Experimental Procedure: WARNING: Wear your safety goggles, safety aprons, perform all tests carefully and follow any additional warnings that follow!!!!!!!!!!!!! REMEMBER! Be SURE to use CLEAN EQUIPMENT that has been THOROUGHLY rinsed with distilled water at least three times. Preliminary steps: Although we will not get to the single replacement reactions for a bit, we’ll start a couple early so they have time to react as these tend to be slow reactions. 1. Copper (Cu) Metal in Silver Nitrate (AgNO3 ) After taking careful observations of both the copper metal and the 0.4 M silver nitrate solution, place the copper metal in about 1.0 mL of the solution in a SMALL test tube. Set aside and allow it to react undisturbed until called for later in this experiment. 2. Zinc (Zn) or Aluminum (Al) and Copper (II) Sulfate (Cu(SO4 ).6H2 O) After taking careful observations of both the zinc or aluminum metal and the 0.4 M copper (II) sulfate solution, place the metal in about 1.0 mL of the solution in a SMALL test tube. Set aside and allow it to react undisturbed until called for later in this experiment. Addition Reactions: 1. Cyclohexene (C 6 H10 ) and Bromine (Br2 ) DEMONSTRATION ONLY In the fume hood, you will see Cyclohexene and Bromine. Carefully take observations regarding these two reagents. Decide wha...
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This note was uploaded on 09/18/2012 for the course CHEMISTRY 1010 taught by Professor Kumar during the Fall '11 term at WPI.

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