Luis Ruvalcaba
4-10-14
Lab-31
Utilizing Copper To Determine The Percent Yield
Abstract: In this experiment the percent yield was determined by dividing the actual yield
by the expected yield of copper. The actual yield was obtained by subtracting the mass of the
empty beaker from the mass of the beaker plus the copper. The expected yield was determined
by the doing a mass to mass problem. The result is accurate; the percent yield for copper is
90.5%.
Introduction:
In this world we have an element that is used in many types of things. This element is copper.
Two of those things made from this element are pennies coins and electric wire. Copper is a
very soft metal, and with a reddish color. Copper is also a very good type of wire used as a
conductor of electricity and heat. Copper as silver is very flexible and can be maneuver without
a pair of pliers. Copper maintains its integrity through a series of chemical reactions and it has
an advantage of being very economic for users.
In this investigation you will perform a chemical reaction involving copper and other
copper compounds. Then you will calculate the expected yield from the mass to mass problem
then you will divide the actual yield by the expected yield after that multiply by 100 to get the
percent yield.
Purpose:
The purpose of this investigation is to calculate the expected yield from the chemical reaction
and then divide the actual yield by the expected to determine the percent yield of the copper.
Procedures:
Determine the mass of a clean, dry 100-ml beaker. Measure 8.0g of copper sulfate crystals and
add these to the beaker. Measure 50.0 ml of water in a graduated cylinder and add the water to
the crystals in the beaker. Them place the beaker in a hot plate and heat it, but not let it boil
keep. Continue heating and stirring the mixture with the stirring rod until the crystals
completely dissolved. Measure 2.24 g of iron filings. Add the iron filings, little at a time to the
copper sulfate solution, stirring continuously. When you get it off the the hot plate let it cool for
10 minutes. Decant the whole amount of liquid into a beaker of 250- ml then gently pour the
liquid down the stirring rod into the beaker. Don't try to move, or touch the bottom of the
beaker. Add about 10 ml of water to the solid in the 100-ml beaker, stirring vigorously allow
the solid settle and decant again. Spread the solid in the bottom of the beaker and let it dry.
After the solid is completely dry, find the mass of the beaker and the solid copper. Record these
masses in the data table.
Results:
Mass of empty beaker
Mass of beaker plus copper
Actual yield of copper
Expected yield of copper
Percent yield of copper
49.1 Grams
51.6 Grams
2.3 Grams
2.54 Grams
2.3/2.54 *100% = 90.5%
Conclusion:
When we added the iron to the copper sulfate a new reactant was formed the copper
went alone and the iron and sulfate became Feso4. It never passed to my mind that the
expected yield was going to be very similar to expected yield and It was similar. I feel
confident about what the percent yield we obtain by dividing the actual yield by the
expected yield because I have done other percent yield problem before.
For me and my partner the results we got were accurate. By doing the mass to mass
problem I determined the expected yield. It gave me an idea of how much the actual
yield could be. Am pretty sure that most of my classmates got a similar results the we
obtained by dividing the actual yield by the expected yield and then multiplying it by
100 %.
Discussion:
The last result that we obtained for the actual yield of copper was 0.2 grams less than we
got from the first time. When we were adding the iron filings to the copper sulfate we
dropped some of the 2.4 grams we were supposed to add in. Once we add the iron filings
I was the one that was stirring the mixture with the rod and just by a couple of mm I
didn’t drop the whole thing to the floor. I think this lab was a good thing to learn
because some time in our life we are going to face some of these situations where we
have to determine the percent yield of a compound. For example in real life this problem
can be done it, there is a back pack that weights 3 kilograms and the bag with stuff in
weights 5 kilo grams so the actual yield of the stuff is 2 kilograms and the expected yield
is 3 kilograms, so the percent yield of the stuff is 2/3 times 100% and the equals to 66.67%
of the stuff.