Lab 6.1 Double Replacement Reactions.

No, all my predictions werent accurate. The one that didnt match were Potassium Chromate with Potassium Iodide, Copper Chloride with Potassium Iodide, Copper Chloride with Silver nitrate and Potassium Iodide with Silver Nitrate. I think for the first trial i didnt match up because when they were put together, the thing that was formed was already present and for the other trials i think it was just because of a bad prediction that we made while figuring out which one was the solube/Insoluble. I wasnt able to figure out the trials that had results that didnt match with the prediction because alot of my trials didnt match up with the prediction.

Steps to write a double replacement reaction :

• First, Figure out the charges on each of your ions, the charge must equal zero when you add them.

 Pb(NO3)2 + 2 KI (aq) ---> the charge will be Pb = +2, NO3 = -1, k = +1, I = -1.

• Then,do the double replacement to find products and write their formulas

 Pb(NO3)2 + KI (aq) ---> K(NO3) + PbI2

• Figure out which is your precipitate using Table F 

 Pb(NO3)2 (aq) +  KI (aq) --->  K(NO3) + PbI2 (s) 

•  Balance the reaction 

Pb (NO3)2 (aq) + 2 KI (aq) ---> 2 K(NO3) (aq) + PbI2 (s)

5.1 Rates of Reaction

In this experiment we started by making a plan , first we listed the variables that affect the rate of reaction. Temperature, Surface area/Pressure and Concentration of reactant are the variables that we identified, The Higher the temperature the more collisions between the reacting particles and cause the reactions to move faster, also a higher concentration leads to more collisions which increases the rate of reaction and the high surface area lead to more collisions between the reacting particles.For the first test we used 1-2 crushed tablet for every 20 ml of water at Room temperature degree Celsius. For each test we only changed one variable ( either temperature, concentration of the vinegar and non crushed/crushed tablet) it was important to change one variable at the time because if we changed all of them at the same we will not have accurate result of the experiment.If you change all the variables at the same you will not be able to see how one variable affected the experiment because you will have nothing to compare it again.

In the experiment one of the variable that we changed was the rate of the concentration of the vinegar , the temperature of the vinegar and the amount of tablet that was crushed and it influence the rate of the reaction.The less concentrated the solution of vinegar and the water was the more time it took for the reaction to occur,this occured because when you decrease concentration the less collisions you will have. When we changed the temperature of the vinegar the time of reaction also changed, when the temperature was low it took more time to react but when the temperature was high it went faster because the particles are colliding more. The last one was based on the tablet being crushed or non-crushed, the more crushed the alka-seltzer was crushed the less time it took to dissolve in the water because it had a high surface area which make the reaction goes faster and the particles collide more. All of our predictions that we made were correct.

A real life example of Catalyst is Enzyme. Enzymes are protein that increase the rate of reaction.Enzymes work by lowering the activation energy , an example of this is biological cleaning powders are used to break down stains on clothes.