Chemistry Honors Lab: Mole-Mass Relationships Lab

Lab: Moles-Mass Relationships Lab

The purpose of this lab was to test my capabilities of precision in the lab and to also exercise my newly acquired skills in stoichiometry.  Below are pictures of data the my group and I gathered.  That data is also used to answer questions that are located in the pictures as well.  The most likely reason why my group and I didn't get the full 100% yield of salt is that while dripping water down the watch glass to clean the solution that had gathered underneath, we probably missed some water-salt solution which lead to a decrease in the mass of the product, NaCl.

Chemistry Honors Lab: Composition of a Copper Sulfate Hydrate

Lab: Composition of a Copper Sulfate Hydrate

Copper Sulfate Prior to Heating:

Copper Sulfate After Heating:

Amount of Hydrate Used:

46.09 g (Mass of Dish + Hydrate) - 45.21 g (Mass of Dish) = 0.88 g (Copper Sulfate Hydrate)

Amount of Water Lost:

45.67 g - 45.21 g = .46 g CuSO₄ (Copper Sulfate Anhydrate)

0.88 g (Copper Sulfate Hydrate) - 0.46 g (Copper Sulfate Anhydrate) = 0.42 g (Water)

Percentage of Water in Hydrate:

0.42 g (Water) / 0.88 g (Copper Sulfate Hydrate) * 100 = 48% (Water)

Percent of Error:
(Actual percentage of water in CuSO_4 Hydrate: 36%)

((0.48 - 0.36) / 0.36) * 100 = 33% of Error



Predicted Empirical Formula:

a) Moles of Water Evaporated:

0.42 g (Water) * (1 mole / 18.01 g (Water)) = 0.023 mol (Water Evaporated)

b) Moles of Copper Sulfate Anhydrate Remaining:

0.46 g (Copper Sulfate Anhydrate) * (1 mole / 159.6 g (Copper Sulfate Anhydrate) = 0.0029 mol (Copper Sulfate Anhydrate

c) Ratio of Copper Sulfate to Water:

0.0029 g / 0.023 g = 1 (Copper Sulfate) : 8 (Water)

d) Empirical Formula:

1 CuSO₄ * 8 H₂O


Due to my percent of error being significantly higher than anticipated, I believe that my prediction of 8 water molecules for every CuSO₄ molecule is way to high.  After doing the math (see below), I have determined that, in actuality, there are supposed to be 5 water molecules for every CuSO₄ molecule.

Math to prove above statement:

Step 1) Percent to Grams

36% = 36 grams of water
64% = 64 grams of Copper Sulfate

Step 2) Grams to Moles

36 g * (1 mole / 18.01 g (water)) = approx 2 moles

64 g * (1 mole / 159.6 g (CuSO₄)) = approx. 0.4 moles

Step 3) Divide by Smallest

2 moles of water / 0.4 = 5 moles of water
0.4 moles of copper sulfate / 0.4 moles = 1 mole of copper sulfate

5 water molecules for every 1 copper sulfate molecule

Correct empirical formula for the hydrate: 1 CuSO₄ * 5 H₂O

Chemistry Honors Lab: Mole Baggie Lab

Lab: Mole Baggie Lab

This lab's purpose was to determine what substance was in a bag given minimal information.  The information given was either "A": The mass of the bag and the number of moles of the substance in the bag, or "B": The mass of the bag and the number of particles of the substance in the bag.  For my first go at this activity, I received Bag A5 and the substance inside was Zinc Oxide, ZnO.  After my first and only attempt at Set A, I received Bag B3 and inside was Potassium Sulfate, K₂SO₄.  Once finding and calculating data, we were given five substances to compare our results to.

Determining the substaces was not too difficult.  For Set A, I massed the bag and the substance (4.71 g) and subtracted the mass of the bag itself (2.56 g).  Then I used the mass of the substance (2.15 g) and divided that by the number of moles in the given sample.  The final conclusion for Set A was that the substance had a molar mass of 86 g and this value was closest with Zinc oxide having a molar mass of 81.39 g.  For Set B, I massed the bag and the substance (5.99) and subtracted the mass of the bag itself(2.55 g).  Then, I converted the amount of particles of the substance (1.20 x 10^22) to the amount of moles in the bag (0.020 moles).  Then, we took the amount of grams of the sample (3.44 g) and divided it by the amount of moles of the sample (0.020 moles) and found that the substance had a molar mass of 172 g.  This was closest to Potassium sulfate having a molar mass of 174.3 g.

Sample of Potassium Sulfate

Chemistry Honors Lab: Double Replacement Reaction Lab

Lab: Double Replacement Reaction Lab

This lab's purpose was to test my capabilities in predicting products from double replacement reactions and to get my hands on some actual chemical reactions for the first time this year.  The following will be pictures of the ten experiments, six of which reacted.  Hoping for some more chemical reactions, hopefully some explosions.....

Chemistry Honors Lab: Nomenclature Puzzle

Lab: Nomenclature Puzzle

The goal of this activity was to work with a partner and solve a puzzle.  The way this puzzle was solved was by matching the name of a compound and the formula that corresponds with it.  The biggest challenge involved in this challenge was the last five minutes.  The reason being is that when And (my partner) and I were looking for matches, it was difficult to determine whether or not those matches were in the two big chunks or left in the "straggler" pile.  My biggest contribution to this activity was my near constant communication.  Knowing what the other person has and letting him/her what your plan is allows both people to work together more efficiently and expedites the process.

Chemistry Honors Lab: Atomic Mass of Candium

Lab: Atomic Mass of Candium

The purpose of this lab was to test if the experimenters knew how to find and use data to find average atomic masses.  For Candium, my partner and I found that it has an average atomic mass of 1.28 amu.

1. Another group found that Candium had an average atomic mass of 1.25 amu.  This difference is most likely due to the possibility of them having a different sample then my group.

2. If sample sizes or were larger, I believe that the percent of error between groups would diminish due to having more atoms to analyze and therefor have a much more legitimate average than a smaller sample size would.

3. Almost any atom of Candium that had be massed would not equal the average.  The average found, in this case, was not the value of any of the three isotopes: normal, peanut, or pretzel.

4. Cy (Candy-Yum)

Chemistry Honors Lab: Chromatography

Lab: Chromatography

1. The water would not have evenly distributed from the starting point, the center, if it were not for the "wick" to transfer the water to the disk-like filter.

2. The pattern of colors produced on the filter paper could have differed due to the difference in the solubility of the ink used, the company who produced the marker/ink, and the type of marker produced.

3. Black ink is composed of many different colors of ink.  Thanks to the solubility and molecule size of those different inks and the chromatography paper, we can see each ink clearly after the process is complete.

4. The compounds that are used to make blue could differ, but due to the way this experiment was performed, I could not determine whether the compounds were the same or different.  Pigments that were in many of the pens/markers that were tested included blue, a purple-ish pink, and yellow.

5. Only water-soluble pens/markers were used due to the fact that the liquid used to carry out the chromatography process was water.  If this experiment were to test the ink in permanent markers, one could use a stronger liquid, such as alcohol.