Titration Lab

July 6, 2015

The purpose of this lab was to find the percent ionization of vinegar. To find the percent ionization, the volume of NaOH or sodium hydroxide. Using titration to see how much of NaOH made the liquid into a slight pink color, the the volume was discovered to be 27.1 on the first trial and 26.3 on the second trial. The pH of vinegar was given to be 2.4. With all this information in mind, the MV = MV equation could be used to find the molarity of acid.

Trial 1: (X M) (7.3) = (0.25 M) (27.1)  --> 0.94 M

Trial 2: (X M) (8)    = (0.25 M) (26.3) --> 0.82 M

Average Concentration of the vinegar = 0.88 M

[H3O+]  = 3.98e-3

The percent ionization was 0.45% found by dividing the hydrogen ions in vinegar water by the CH3COO- times 100 to find the percent.

The percent ionization was so small because the acid is a weak one.

Soluibility: A Guided Inquiry Lab

July 5, 2015

Introduction:

The purpose of the lab was to identify unknown solid. To identify the solid, the mysterious substance was placed in water to obtain its solubility. Heating water to 44 degrees Celsius, the substance was placed and stirred to see if it would dissolve. Our first attempt dissolved with 3.8 grams of the substance proving that the solid was indeed not NaCl (the lowest solubility possible outcome). Then 3.2 grams were then added to the water for the second trial and it also dissolved, canceling the option of KNO3. The final answer due to elimination was NaNO3.

Procedure:

Materials- hot plates, balances, thermometer, beakers, erlemeyer flasks, stirring rods

1. Pour beaker with 10 mL
2. Put large beaker with 20 mL underneath
3. Heat water to 44 degrees C
4. Add 3.8 grams and check if it dissolves
5. If dissolved, add 3.2 grams and check if it dissolves

Data

Test #1 
 3.8 grams of substance- dissolved --> This canceled out the possibility of NaCl

Test #2
3.2 grams of substance- dissolved-->This canceled out the possibility of KNO3, leaving only NaNO3.

Discussion/Concluding Summary:

The substance found was NaNO3, beacause the solubility levels were on par with NaNO3 which was the only remaining possibility left. The higher the temperature, the solubility also increased.

Alka Seltzer and the Ideal Gas Law

    The purpose of this lab was to determine the mass of the CO2 produced. Using a balloon and 3 Alka Seltzer tablets, we were able to measure the amount of CO2 by measuring the circumference of the balloon and filling it with water till it matched the circumference of the Alka Sletzer tablet sized balloon. 

Analysis Questions

1. We spilled some powder and spilled water on the first attempt.

2. Spilling powder would make "n" a smaller quantity.

3. The volume was 896 cm3/mL.

4. It was mucho close. I believe the actual one is accurate because the balloon is not a perfect sphere.

5. A real gas interacts with others while an ideal is independent of others. In an ideal gas actual volume taken up by the molecules of gas is not taken into account. 

6. No, the ideal gas would not interact with others.

Advanced Questions

1. 2.06 grams is the mass of CO2 that should be collected.

2. 76.7% is the percent yield for the for the CO2. 

3. Our calculations would mean it was less than the actual value since the CO2 dissolved. 

Calories in Food Lab

    In this lab, we were to calculate how many calories three types of food contained. To do so, using measurements for the cashew, pecan, and cheese puff for both after being burned and before was essential. Also a constant 22 degrees for water was established. After the water was burned, the temperature of the water was measured to calculate the change in temperature. At the end, cashew was found to contain 960 calories, Pecan to be 1450 calories, and cheese puffs to be 350. 

Evaporation and Intermolecular Attractions

July 29, 2015

Flame Test Lab

The purpose of the lab was to demonstrate the colors of different chemicals emitted when the electrons of certain chemicals were burned and two chemicals were not revealed. Using the color recorded for each chemical, we were to infer the right chemical present.

Prelab Questions

Unknown 1- LiCl

Unknown 2- ZnCl

I knew the identity of the unknown because the color produced from the unknown got the same color as the chosen chemical tested.

Electron Configuration Battleship

July 28, 2015

The biggest challenge was attempting to utilize the skills we learned in class to verbally and mentally challenge our brains to electron configurate the elements in an organized fashion. I learned to list the electron configurate.

Mole-Mass Relationships Lab

         In this lab, the purpose of the lab was to use stoichiometry to find the percent yield of the solid product by first finding the theoretical yield of NaCl and plugging that in. 

         In this experiment, NaHCo3 and HCl was combined to form NaCl, CO2 and H2O. In order to achieve this, 2.04 grams were added to the evaporation dish and mixed with the acid HCl. Then to separate the H2O, the hot plate was used to evaporate the water and leave only the salt. 

1. NaCO3 is the limiting reactant because    there is a limited amount and is the only reactant not to be renewed. 

2. The theoretical yield of was 1.42 grams found by using proportions to cancel units out.

3. The mass of the remaining solid product after the evaporation of water is 1.38 found by subtracting 44.83 (mass of evaporating dish) from 46.31 (mass of e.d + remaining solid product).

4 The percent yield for this experiment is 97.2 found by dividing the actual yield (1.38) by the theoretical yield (1.42) times hundred. 

I believe the reason why our result was so close yet not exact was the way we were heating the products of the equation for. The more you heated it, the more water and grams fell. 

Composition of A Copper Sulfate Hydrate Lab

July 25, 2015

Composition of a Copper Sulfate Hydrate Lab

1. The mass of the hydrate used was 0.99 grams.

2. The mass of the water lost is 0.34 grams.

3. The percentage of water in the hydrate is 40%.

4. 11% was our percent error. Possible explanations for this error may have been inaccurate readings of the mass of the Copper Sulfate Hydrate or insufficient time to heat the substance.

5. 

a) 0.019 was the number of moles of water of water evaporated. 

b) 0.0041 was the number of CuSO4 remaining. 

c) 5 was the ratio of moles from CuSO4 to H20.

d) CuSO4 x 5H20 was the empirical formula.

My percent error was high and I believe that the coefficient for water is lower than the actual coefficient.

Mole Baggie Lab

July 24, 2015

Mole Baggie Lab

      In this lab, we were given two sets of bags one (A6) labeled with the number of molecules and another (B1) labeled with the number of grams. With this information, the Molar Mass was to be calculated. When the mass is calculated, there were five possible compounds that each baggie could be. There was sodium chloride, Potassium Sulfate, Zinc Oxide, Sodium Sulfate, and Calcium Carbonate.
      A6 ended up with a molar mass close to Sodium Sulfate. B1 resulted in the same possible compound as A6.
      To find the molar mass for A6, first the # of grams had to be found. The bag was first weighed and the weight of the bag was subtracted from the whole mass. Then the # of grams was divided by 0.045, which was the number of moles.
       To find the molar mass of B1, the number of grams were given and the number of moles had to found. For this, a conversion was needed to find to find the number of moles. After that the molar mass could be found. 

Double Replacement Reaction Lab

July 23, 2015

What surprised me the most was that the solution moved both in a liquid and solid way in the petri dish. I didn't expect the substance to be moving in gel like movements and it was very surprising in general.