Lab 6: Mole-Mass Relationships Lab

In this lab, we created a chemical reaction by combining Sodium Hydrogen Carbonate and Hydrochloric acid. Then we separate the solids and hydrate, and try to find how much NaCl is left as a solid. 

Sodium Hydrogen Carbonate and Hydrochlorate Acid

We used a dropper to combine the acid and carbonate

We heated up the solution to separate the hydrates and solids

The NaCl that was left behind

 We extracted 90% of the NaCl that we should have. This was most likely because some was removed when we moved it using tongs, or when it was being heated, some of the NaCl popped out.

Lab 5B: Composition of a Copper Sulfate Hydrate Lab

We took a sample of carbon sulfate hydrate and tried to find the ratio of carbon sulfate and H2O.
We heated up the sample in an evaporation dish to find out how much water was in the sample and calculated the ratio.

Copper Sulfate Hydrate

Heating up the Copper Sulfate Hydrate

All the water has evaporated from the compound to create Copper Sulfate

1. Calculate the mass of the hydrate.

(Mass of evaporating dish and hydrate) - (mass of evaporating dish) = Mass of hydrate

45.88 - 44.97 = .91 grams of copper sulfate hydrate



2. Calculate mass of the water lost.

(Mass of evaporating dish and hydrate) - (Average of Mass of dish and hydrate after heating 2 times) = Mass of Anhydrous salt

(45.22+45.68)/2 = 45.45 = Average of Mass of the dish and hydrate after heating it twice

45.88 - 45.45 = .43 grams of water


3. Calculate percentage of water in the hydrate.

(Mass of Water)/(Mass of total hydrate)= percentage of water in the hydrate

(.43)/(.91) x 100 = 47% water 


4. Calculate percent error.

Actual percent is 36%               (|Experimental Value - Actual Value| / Acutal value) x 100 = % error

(|.47-.36| / .36) x 100 = 30.5 % error


5. a) moles of water evaporated

1 mole of H20 = 18.0148 grams
conversion:
(.43 g H2O/1) x (1 mol/18.0148 g H20) = .0238 moles of H20

b) Moles of CuSO4 that remain in evaporating dish:

1 mole of CuSO4 = 159.61 grams
conversion:
(.48 g CuSO4/1) x (1 mol/ 159.61 g CuSO4) = .003 moles

c) Find the ratio of moles of CuSO4 to moles of H2O.

.003/.003 = 1
.0238/.003 = 7.9 or 8
1 to 8

d) What is the empirical formula of the hydrate.

(CuSO4)1 (H20)8


However, because our percent error was fairly high, we predict a different result. Our percent of water lost is greater than the actual answer so the real coefficient for water should be smaller than eight.

Lab 5A: Mole Baggie Lab by Katie and Maya

In this lab, we received a plastic bag with an unknown substance in it. However we knew the mass of the empty plastic bag and the number of moles in the bag. From this information we had to find what substance was inside the bag.

We took the mass of the plastic baggie and and subtracted the mass of the empty plastic bag. WE found the mass of the substance in grams and divided it by the number of moles (0.045 moles) to find molar mass. Our five options were sodium chloride, potassium sulfate, zinc oxide, sodium sulfate, and calcium carbonate. After calculating the molar mass of these compounds, our result were closes to Sodium Sulfate.

Our bag A6 contained Sodium Sulfate.

Lab 4A: Double Replacement Reaction Lab by Katie and Maya

In this lab we experimented with different combinations of solutions to see if they form a solid precipitate. 

Even though Ms. K warned us about what the precipitate looks like I had expected a solid produced by a chemical reaction to be more structured and a little less fluid looking. However the precipitate caused the substances to become a little cloudier rather than clear. 

It difficult to be precise with the dropper! We were probably inconsistent with the amount of different chemicals in the reaction. This skill will probably come with time and practice. 

A precipitate can make the liquid look cloudy 

Here are all the equations of the chemical reactions with the net ionic equations listed below. 

At first balancing the chemical equations was also difficult but once I got used to the process it was easy to go through the steps of the process. 

Lab 3 Activity: Nomenclature Puzzle

The goal of this lab activity was to finish a puzzle matching the formula to the name of a chemical compound. For example one puzzle piece might say KNO3 and we had to match it to the puzzle piece that said Potassium Nitrate. This helped us practice naming compounds of Types 1, 2 and 3.

The biggest challenge was probably trying to locate all the matching pairs that were written in different directions. Also, there were so many! Once we had major pieces of the puzzle together, it became easier to locate these pairs.

My biggest contribution was matching together different formulas and names. Once we sorted the different elements, it became clearer which ones should be together, so I tried to match them in an efficient way.

Lab 2B: Atomic Mass of Candium by Katie and Nick

Purpose: The purpose of this lab was to try and find the average atomic mass of an "element" Candium. Candium has three "isotopes": regular, peanut, and pretzel m&ms. This helped us understand what the atomic number of an element really means and how to apply it when learning the different isotopes of an element.

Average Atomic Mass of Candium: 1.52 grams.

1. Ask a group nearby what their average atomic mass was.  Why would your average atomic mass be different than theirs?

We may have a different abundance of different isotopes. For example we had more m&ms with a larger mass than they did, so our average atomic mass went up. The abundance of each isotope affects the average atomic mass of an element.

2. If larger samples of candium were used, would the differences between your average atomic mass and others' average atomic masses be bigger or smaller? Defend your answer.

The differences would become smaller. As the sample increases, our abundances of each isotope is more likely to become closer together. Therefore our all of the average atomic masses become more accurate and closer to each other.

3. If you rook any piece of Candium from your sample and placed it on the balance, would it have the exact average atomic mss that you calculated?

No. The average atomic mass will not match the exact mass of any piece of candium. Since Average atomic mass is an average, it will be slightly higher or lower than any given isotope.

4. Here is the element square for candium!

Lab 2A: Chromatography Lab by Katie and Nick

Chromatograph #1 After the water

Chromatograph #1 before the water   

                                         

Chromatograph #2
Chromatograph #1

1. Why is it important that only the wick and not the filter paper circle being contact with the water in the cup?

The ink from the marker is being carried through the filter paper gradually by the water. This way we can see which substances are quickly absorbed into the paper and which ones can travel farther up the paper with the water. If the paper were fully submerged in the water, we would not be able to see the differences in distance travelled by different substances.

2. What are some of the variable that will affect the pattern of colors produced on the filter paper?

The distance from the center affected what kind of design appeared on the paper. We also learned that drawing various shapes and lines on the paper will change the design. The ink from different markers produced different colors. Somer were very colorful, others were just blue or black. Leaving the paper on the wick will allow the water to dilute the color more. For example, the bottom design was left in the water longer than the top design.

3. Why does each ink separate into different pigment bands?

Depending on what substance makes up the ink, some inks are easily absorbed into paper while others can flow through it easily like the water. From our observations, orange and yellow stay close to the middle because it stays printed on the paper. However, pink can travel farther than that and light blue is always out on the very edge.

4. Choose one color that is present in more than one type of ink. Is the pigment that gives this color always the same? Do any of the pens appear to contain a common pigment?

Light blue was a color used in many of the inks. Repeatedly light blue was the one that always spread out the furthest. The similarities between the chromatograms shows that different pens appear to use same pigments.

5.  Why are only water-soluble markers or pens used in this activity? How could the experiment be modified to separate the pigments in "permanent" markers?

Water soluble markers can be broken down when the water passes through the ink. Therefore, it is easier to see the separation of the pigments when they spread out on the adsorbent along with the water. Using a solvent that can break down the different pigments in the ink of a permanent marker will allow us to create a chromatograph using a permanent marker.