Lab 6: Mole-Mass Relationships Lab

The purpose of this lab was to practice calculating theoretical yield and percent yield using our experimental data. We also had to find the limiting reactant of NaHCO3(s) + HCl(aq) => NaCl (aq) + CO2(g) + H2O(g) by looking at the relationship between the reactants and how much product they each produced. Overall, we found that NaHCO3 was our limiting reactant and we were able to successfully have a 100% yield.

Questions #1-#4

 

 

Even though our percent yield was 100%, I believe we did lose some mass when our remaining solid product popped once on the hot plate, but the small amount of water still left in the evaporating dish made up for that lost mass. The fluctuating of the scale is also another reason that error may occur and it could've possibly affected our percent yield if we did not read the scale as accurately as we did.

 

 



My lab partner and I also found it interesting that when we touched the tongs to the remaining solid in the evaporating dish, the solid turned into a yellow-green color due to contamination. 

 

Lab 5B:Composition of a Copper Sulfate Hydrate Lab

Before heating

After heating

Calculations for Questions #1-#4

Possible explanations for percent error include the false reading of the scale while it was fluctuating or not waiting long enough for all the H2O to evaporate.

Question #5
Moles of water evaporated- 0.014 mol H2O
Moles of CuSO4- 0.0032 mol CuSO4
Ratio of moles of CuSO4 to H2O- 1:4
Empirical formula- 1CuSO4 is loosely bonded to (dot symbol) 4H2O
We predict our predicted coefficients are slightly low compared to the actual value, even though our percent error isn't high.  To have a percentage of water closer to 36%, more water needed to be lost and therefore the ratio of Copper Sulfate to water would increase. 

Lab 5AL Mole Baggie Lab

In this lab, we needed to determine mystery substances in plastic bags using given measurements of the substance. We began by weighing the filled bag on the scale to find the total mass, and then we also used our given total mass to find the mass of our substance. For Set A, we calculated the molar mass by dividing the mass of the substance by the given number of moles. For Set B, we first converted the given number of respective particles to moles, and then we calculated the molar mass using the same given formula. Next we compared our calculated molar masses to the molar masses of the possible compounds. Our results were A4 is Calcium Carbonate and B3 is Potassium Sulfate.

Lab 4A: Double Replacement Reaction Lab

Complete molecular and net ionic equations #1-#5



Complete molecular and net ionic equations #6-#10

 



My well plate

 In this lab, I was surprised on how easy it was to write net ionic equations. After I completed writing the molecular equation for each reaction, I used any solid products to write a separate net ionic equation beneath. The shortcut of breaking down the solid compound to its separate polyatomic ions and elements made it very easy to write the net ionic equation. The most challenging part of this lab was finding out the solubility of each compound in the complete molecular equations. I needed to continually look at the solubility rules to find out what compounds were insoluble or soluble. The many exceptions in the solubility rules made this even more challenging.

Lab 3: Nomenclature puzzle

The goal of this lab was to complete a puzzle by matching binary and polyatomic ion formulas to their name. This puzzle was good practice on using the naming rules we learned in class today. The biggest challenge during this activity was searching for certain names that were already part of small groups. At the beginning, it was more simple to match names and formulas because we divided by the triangle pieces by the elements on the triangle, but it became more difficult as more and more small groups formed. I believe my biggest contribution to the group was putting the small groups of triangles together, making it easier to find certain triangles. I also helped assign certain elements to certain people, making the process flow more quickly.

Our completed puzzle

Lab 2B: Atomic Mass of Candium

In this lab we used three different isotopes of candium: regular M&M's, peanut M&M's and pretzel M&M's. The purpose of this lab was to practice calculating average atomic mass and to understand isotopes. We also were able to apply our new terms such as atomic number, atomic mass and natural abundance. Our calculated average atomic mass of candium was 1.357g. 

Conclusion:
     1. We compared with another group and found their average atomic mass to be 1.689g. It is possible they have a different answer than us because of human error such as counting incorrectly or not properly weighing the M&M's. It is also possible that each group started with a different amount of each type of M&M, therefore having a differing average atomic mass.

     2. If everyone were given a larger sample of candium, the difference between our average atomic mass and everyone else's atomic mass would become smaller because the larger sample size would create a more similar ratio of each type of M&M's and therefore the result would be more precise.

     3. If we took any piece of candium from the sample and put it on the balance, it wouldn't have the exact same atomic mass that I calculated because each type of M&M has its own distinct weight and none of the M&M's alone could weigh the average mass.

     4.

Lab 2A: Chromatography

 

My favorite chromatogram

Lab Questions:

     1. The wick was used to slowly add water to the center of the filter paper and this lab only works when you can visually see the separation of pigment. If we soaked the filter paper itself in the cup of water, the separation of colors on the paper would be too quick and wouldn't be clear which defies the purpose of this experiment.

     2. Different types of ink with various amounts of pigments affects what colors appear on the paper. I also found that more ink on the paper changed the color to a more darker tone. The distance the ink is from the wick and the design drawn also affect the pattern of colors produced.

     3. Different components of the ink have various physical properties and these properties determine how adsorbent certain pigments are to the filter paper. Components in the mixture that are more adsorbed to the paper will move more slowly compared to components in the mixture that aren't as adsorbed to the paper. These not so strongly adsorbed components spend more time ion the solution and move up the paper quickly. The various properties and adsorbing of pigments results in different pigment bands.

     4. Blue appears in more than one type of ink and the same shade of blue always appears. This light blue color was found on the edges of multiple chromatograms which means the blue pigment was not strongly adsorbed by the filter paper. All the markers appeared to have this common blue pigment.

     5. Water is needed to separate pigments in water-soluble markers because the water allows the components in the ink to adsorb to the filter paper which creates the chromatograms. To separate pigments in other types of markers or pens, different solutions would be needed.