Lab+7.5.1

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=Purpose: = The purpose of this experiment is to observe the single displacement reaction that occurs when copper reacts with silver nitrate. There will indeed be a single displacement reaction because according to the activity series copper is above silver, therefore it is expected that copper reacts with nitrate. Also to be observed in the experiment is the limiting reagent and the excess reagent.

=Question: = What makes the copper nitrate blue, and what causes this reaction to be obtained?

=Hypothesis: = The mass of silver nitrate used should effect the percentage yield, by either increasing or decreasing the percentage yield. This is because the more mass of silver nitrate is used, the more chance of impurities found in the silver nitrate, thus the actual yield will be a lot more different than the theoretical yield, hence a higher/lower percentage yield than normal.

=Materials: = = = =Procedure =
 * Safety goggles
 * Latex or rubber gloves
 * Lab apron
 * 100ml beaker
 * Ice cream stick
 * Stirring rod
 * Balance
 * 250ml beaker
 * 30cm copper wire
 * Aluminum foil
 * Distilled water
 * Silver nitrate, AgNO3 (s)

27) The recorded data was posted on moodle.
=Procedure (Technological: wiki spaces): =

1) To create a wiki for this project, first go to http://www.wikispaces.com/ 2) Next click the Teacher button under Teachers & Students 3) Now click: Sign up and start your wiki 3) This will take you to a small form, fill in the form with your information. Under Make a Wiki, select yes, and give a name to it, in the next panel. Now pick your permissions, and the type of wiki, being created. **Figure 2: Beaker with Copper, and Silver Nitrate**

4) Once done you will be brought to your own wiki, you can then go to under the Members section to invite new members, or under the Manage Wiki section, press members, then go under permissions, then press allow membership requests, to allow people to request membership. In this panel, you can also edit the different permissions given to users. Note: Only creator's/admins can use this panel. 5) To create a page to do your project, you can either press projects under Wiki Home, or go to Pages and Files. On the top right in Pages and Files, you can press new page icon, which creates a new page. 6) To edit the new page you must be a member and can simply press Edit on the top right. Note: currently anyone can look at this wiki, if they know the URL, but only the current group using this wiki can edit/create pages. This is due to the fact it costs money to make it fully private, and it will create a lot of hassle, trying to make sure you, the teacher, can see this site to mark it. =Procedure (Technological: commenting / looking at who did what aspect of assignment) =

1) To find out who did what in this project, you can press the view revisions button. This shows every single person who worked on said page, and at what time. You can then select 2 of the revisions by pressing the select button under the Compare category. This will then show you the changes between both copies. Thus showing who added what to this page. To make it simpler, in the discussions section, we have specified who did what section. 2) To add your own comments for marking you can simply press edit, then press Comment, this will bring up a sticky note much like in our flex-book assignments. 3) To add a rubric, you can simply upload it under Pages and Files, then click upload.

=Observation: = Table 2: Observations - During the first day we noticed nothing had happened, there was no reaction occurring, but the next day, the solution turned blue, and there were small needle-like structures sticking out of the copper. When we started removing the silver, it seemed like bits of copper might have been removed as well. Once we decanted, the substance had a silver/copper tinge to it, we decided to keep decanting the solution in order to get rid of as much of the copper colour substance as possible.
 * __ Qualitative __ || __ Quantitative __ ||
 * Mass of copper wire= 0.87g || Mass of silver nitrate=1.12g ||
 * Copper nitrate || Mass of silver=111.27g ||
 * Copper after experimentation =0.65g || Percentage Yield=180.28% ||
 * Beaker=109.99g || Mass of Dry Silver Residue=0.71g ||

=Analyze and Evaluate: =

(a) Based on observations, the limiting agent would be AgNO 3. This is because according to the chemical equation, for every 2 moles of AgNO 3, there is 1 mole of Cu. As such 2 moles of AgNO 3 is 339.74 grams, while 1 mole of Cu is 63.5 grams. So for every gram of Cu there needs to be 5.3 grams of AgNO 3, which is not the case here, as there is only 1.12 grams of silver nitrate for 0.87 grams of copper. So the limiting agent is AgNO 3.

(b) Therefore the theoretical yield is 0.71 grams silver.

(c)

(d)
 * Table 1: All PM & AM group raw data**

(e) The copper nitrate is blue due to the light. This light allows the compound to absorb some of the color, if light was not absorbed the solution will remain as a clear solution.

(f) The percentage yield could be increased if the silver nitrate was more that the obtained amount. By increasing the amount of silver nitrate we will be able to increase the theoretical yield because the theoretical yield is directly proportional to the amount of silver nitrate used in the reaction. Another way to have an increased percentage yield is due to the excess copper particles that are still calculated as the actual yield. And according to the percentage yield formula the actual amount is divided by the theoretical yield, therefore having an constant theoretical yield and an increasing actual yield will resulting in having a greater percentage yield.

(g) i) Calculating the mass of silver residue that is not completely dry will affect the percentage yield because the water in the silver residue will give it addition weight to the silver residue causing the percentage yield to increase. This is because the calculated mass of the silver nitrate will be considered as the actual yield, and with the theoretical yield remaining constant and also having a greater actual yield, will cause the percentage yield to be higher than it should be.

ii) Old silver nitrates does not have high reactivity, therefore there will be less silver residue left after the reaction causing us to have a very low actual yield. And since the actual yield is low the percentage yield will be low too, because the actual yield and the percentage yield are directionally proportional to each other.

iii) Tap water has chloride ions which react with silver ions, therefore there will be more silver residue casing an increase in the actual yield, thus increasing the percentage yield.

=Apply and Extend: =

h) A way to remove the copper (II) ions is by using qualitative chemical analysis. This is used to study the separation and identification of the chemical compound since copper (II) is a low solubility compound we need to find a element with a high solubility compound like iodine. When you place iodine into the solution it will remove all copper (II) ions, giving you nitric acid.

i)To convert silver back into silver nitrate you would need nitric acid as well as the silver we already have. First place the nitric acid into a beaker, after placing the silver into the nitric acid heat up the solution until the silver bubbles. Next weight the solution until the silver is fully dissolved, the formation of crystals (small white powdery substance) will start to appear. Since this is what we are looking for, we are done. Be sure to wear gloves and safety goggles for safety reasons.

=Sources of Error: =

- There are many ways we could have had errors, due to the face this lab had a lot of variables. We might have used silver nitrate which is not completely pure silver nitrate, or there might be impurities on the copper wire, since many groups did not sand the copper wire, to get rid of any dirt present. There also could have been problems decanting, in which we got rid of some silver with the water. Another big problem might have occurred when extracting the silver from the copper wire, we could have been very forceful with removal, and we could have removed some copper in addition to the silver, thus giving us ridiculous values for actual yield. We also might have made a mistake measuring the mass of the silver, etc, as the scale was very sensitive, and might have responded to another source for mass.

=Reference: =

- Grade 11 Chemistry Textbook - [] - [] - [] http://www.wikihow.com/Make-Silver-Nitrate