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CHEM 111L Lecture Notes - Lecture 10: Filter Paper, Molar Mass

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kurtzkm
18 Apr 2019
School
College of Charleston
Department
Chemistry and Biochemistry
Course
CHEM 111L
Professor
Guirgis

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Document Summary

Experiment 10 - limiting reactants, synthesis and decomposition of transition metal. Perform calculations involving limiting reactants, theoretical yields, and excess reactants. Definition of a hydrate: a compound that has a specific number of water molecules within its solid structure. The molar mass of the water molecules is included in the total molar mass of the compound. Weigh approximately 4. 00 g of your assigned metal hydrate and record this in your notebook. Dissolve this in 20. 0 ml of distilled water. Once dissolved, slowly pour this solution into 50 ml of oxalic acid. Continue to stir until solid begins to form. Weigh a piece of filter paper and record this in your notebook. Use a tube to connect the vacuum to the side arm of the flask. Place the piece of filter paper in the funnel and dampen it with water so that it sticks to the plate of the funnel and covers the holes.

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Related Questions

This is Trivalent metal acetylacetonates lab questions.

identify which is the limiting reagent and based on this list how much to take of each reactant and calculate the theoretical amount of product to be expected. In other words, calculations of how much you need to take of each reagent/solvent, identify the limiting reagent and how much product you expect to get assuming 100% yield. You should show your calculation making sure to include the units when appropriate and the correct number of significant figures.

please help me...

Comments

    Calculations First Trial UPDATED

    Theoretical yield (CaCO3):

    Actual yield (CaCO3):

    Percent yield:

    Moles of Ca present in original solution, based on actual yield:

    Mass of CaCl2 present in original solution, based on actual yield:

    Can someone please help me with these three easy questions please? Thank you! SHOW ALL WORK!!

    THIS IS MY DATA FROM MY LAB EXPERIMENT. I JUST NEED FOR YOU TO FIND THE ANSWERS TO THE ABOVE QUESTIONS WITH WORK SHOWN!

    Table 1: Data and Observations

    Mass

    CaCl2 :

    ORGINAL MASS: 2.0g

    AFTER 24 HOURS 5.8g

    K2CO3 :

    2.5g

    Filter Paper

    2.1 g

    Watch Glass

    33.6g

    Precipitate

    3.3g

    Procedure

    Put on your safety glasses and gloves (provided in your safety box).

    Turn on the scale by pressing the button labeled "0/T". If your scale does not turn on, you may have to remove the battery cover and remove a small strip of plastic from the battery housing. Once the scale is on, press the "0/T" button a second time to zero the scale. Make sure that the units are in grams (g). If not, press the M button until the units displayed are in grams.

    Place a weigh boat on the scale and record the mass in Table 2. Zero the mass of the weigh boat by pressing the "0/T" button. Your scale should now read 0 g.

    Add 2.0 g of CaCl2 to the weigh boat. Record the mass in Table 2. Set this sample aside, and let it sit exposed to the air (but otherwise undisturbed) for 24 hours. Complete Steps 3 - 23 while you wait.

    Place a 250 mL beaker on the scale and zero it.

    Add 2.0 g of CaCl2 to the beaker. Record the exact mass of the powder in Table 1.

    Remove the beaker from the scale. Use a 100 mL graduated cylinder to measure and pour 50 mL of distilled water into the beaker and mix with the stir rod until all the CaCl2 has dissolved.
    Note: This is an exothermic process, so the beaker may become warm.

    Place a 50 mL beaker on the scale and zero the scale.

    Add 2.5 g of K2CO3 to the 50 mL beaker. Record the exact mass of the powder in Table 1.

    Remove the beaker from the scale. Use the 100 mL graduated cylinder to measure and pour 25 mL of distilled water into the 50 mL beaker. Mix with the stir rod until all the K2CO3 has dissolved.

    Rinse the stir rod with water.

    Add all of the K2CO3 solution to the beaker containing the CaCl2 solution. It is important that all of the K2CO3 is added to the beaker. To ensure this, rinse the 50 mL beaker with up to 5 mL distilled water, and pour the rinse in the CaCl2 solution.

    Using the stopwatch to keep time, stir the solution with the stir rod for four minutes. Then, allow it to sit for 15 minutes. This will allow sufficient time for the chemical reaction to occur.

    Rinse the stir rod with water.

    Place a piece of filter paper on the scale and record the mass in Table 1.

    Place a watch glass on the scale and record the mass in Table 1.

    Fold the filter paper in half and in half again so that it resembles a triangle with one arched side.

    Pull apart one fold of the filter paper so that three sides of the filter paper remain together, with one side making up the other half of the funnel shape (Figure 5).

    Hold the funnel over a sink or any sized container. Place the paper into the funnel and use a pipette to drip 5 mL of distilled water around the edges of the filter paper. This will prevent the filter paper from rising up out of the funnel.

    Rest the funnel on top of the Erlenmeyer flask.

    After 15 minutes has passed, swirl the beaker and slowly filter the solution (that you created in Step 9) from the 250 mL beaker through the filter paper. Additional distilled water may also be used to transfer any remaining solid into the filtration apparatus.

    After all the solution has been filtered, use the pipette to rinse the filter paper with approximately 5 mL of isopropyl alcohol to aid the drying process. Allow the isopropyl alcohol to completely drip through the filter before removing filter paper from the funnel.

    Carefully remove the filter paper. Unfold and place it precipitate-side up onto the pre-weighed watch glass. Be sure not to lose any precipitate during this transfer.

    Allow the precipitate to dry, undisturbed, for at least 24 hours. Determine the mass of the product recovered by re-weighing the system and subtracting the weight of the filter paper and watch glass. Record your data in Table 1.

    Re-weigh the sample of CaCl2 that was allowed to sit exposed for 24 hours. Subtract the mass of the weigh boat and record the mass and your observations in Table 2.

    TABLE 2 IS NOT IMPORTANT IN SOLVING THE QUESTION AS IT JUST ASKS FOR MY OBERVATION OF CaCl2 AFTER 24 HOURS. ALSO TO FIND THE ACTUAL YIELD, YOU WOULD HAVE TO FIND FIRST THE PERCENT YIELD AND THEORTICAL YIELD.

    Part 1: Separation of Iron filings

    1. Mass a watchglass and record
    2. Obtain a Kimwipe tissue from the top of the benches and a rodmagnet
    3. Wrap the Kimwipe tissue around the magnetic end, holding thetissue tight to the rod magnet.
    4. Swirl the Kimwipe in your mixture. Knock off excess sand beforemoving on to step 5
    5. Carefully over the watch glass remove the Kimwipe tissue fromthe magnet so the iron falls on the the watch glass
    6. Repeat steps 4 and 5 two more times, make sure you record howsuccessful this separation was � does the evaporating dish containonly iron?
    7. Mass the watchglass and the collected iron.
    8. Dispose of the iron in the hood.

    Part 2: Separation of N

    1. Mass a clean, dry, evaporating dish.
    2. Pour the leftover mixture from step 1 into the evaporating dishand mass.
    3. Place the evaporating dish on a hot plate in the hood.
    4. Gently and slowly heat the mixture until the white fumes cease.Be patient. Depending on the amount of ammonium chloride in yoursample, this could take quite a while. A half our would not beunheard of.
    5. Stir the mixture frequently to facilitate the sublimation ofthe ammonium chloride. This is crucial in order to obtain goodresults. (Use crucible tongs to hold onto the dish so it doesn�tmove as much)
    6. After the white fumes disappear, turn off the hot plate andremove the evaporating dish with crucible tongs and let it cool inthe hood.
    7. When the evaporating dish is cooled, mass the left overmaterial and the evaporating dish.

    Part 3: Determining the amount of NaCl.

    1. Measure 10 mL of distilled water in a graduated cylinder.Slowly add the water to the mixture in the evaporating dish whilecontinuously stirring with a clean, glass stirring rod. Afteradding all of the water, stir for 2 min more.
    2. Assemble the gravity filtration apparatus shown in Figure1.
    3. Fold a piece of filter paper as shown in Figure 2. Open up thepaper cone, and place it in the filtering funnel.
    1. Position a beaker under the funnel, making sure that the funnelstem is touching the inside wall of the beaker. Pour as much of thesupernatant liquid as possible from the evaporating dish intofunnel. Collect the filtrate in the beaker.
    2. Transfer the solid remaining in the evaporating dish into thefunnel, using a stream of distilled water from a wash bottle, asshown in Figure 3.
    3. Re mass the watchglass from Part 1 and record this mass.
    4. Pour the filtrate in the beaker into the evaporating dish
    5. Place the evaporating dish containing the filtrate on a hotplate. Begin heating the solution.
    6. While the solution is heating to boiling, move onto Part 4
    1. Carefully remove the filter paper and residue from the funnel.Place the paper and residue onto the watchglass.
    2. Place the watchglass with the filter paper and sand on top ofthe boiling salt solution to dry the sand
    3. Keep the salt water boiling, until there is just a little bitof water left, or popping sounds are heard, then turn off the hotplate, and allow the heat from the hot plate to finish evaporatingand drying your salt.
    4. Allow the evaporating dish and its contents to cool to roomtemperature.
    5. Obtain another watch glass and mass.
    6. Transfer the dried sand and filter paper from original watchglass (caution, salt has spattered onto this watch glass, so don�tknock any off, that is product you will need) onto the new cleanmassed watch glass. Replace the original watch glass onto thecooling evaporation dish
    7. Mass the new watch glass, sand and filter paper all together.Discard filter paper and sand into garbage. Observe how pure yoursand looks.
    8. After evaporating dish has cooled, determine the mass of theevaporating dish, watch glass plus NaCl. Record this mass. Then,discard the NaCl as directed. Wash evaporating dish and watch glassto dissolve the salt.
    9. Observe how pure your salt looks.

    Result and Discussion: Separation Lab

    Substance

    Grams recovered

    % mass

    Fe

    NH4Cl

    NaCl

    SIO2

    Overall percentRecovery:

    A) Explain what steps(s) youcould have improved (and how) to help your percentrecovery.

    b) Write a paragraph about thelab include briefly what was done, your result, were you correctand possible experimental errors- do not state human measurementerrors as errors. Be Specific, what specific human errors occurred,what measurement errors occurred, what process in the experimentcould errors have occurred.