CHEM 1111 Lecture Notes - Lecture 4: Litmus, Tare Weight, Watch Glass

19 views2 pages

lemonfrog498

8 Nov 2014

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Part 1: synthesizing alum: cut pieces of aluminum into thin strips, obtain a number of these which together weigh about 0. 5g and place into a 150 ml beaker, add 25 ml of 1. 5 m koh solution. Place the funnel in a wooden funnel holder and collect the filtrate in a 250 ml beaker. Cool to room temperature: begin adding 10 ml or 9 m h2so4 in 2-3 ml portions. Observe the color of the litmus paper: add one or two drops of 0. 5 m bacl2 solution to the alum solution in the test tube and record observations. Once this is done, dispose of the contents of the test tube into the barium lab. Byproducts jar: place a small amount of solid alum product on a watchglass. Clean the provided wire loop by dipping it in a solution of concentrated hcl and placing it in the bunsen burner flame until it glows red hot.

Related Questions

Miniscale nitration of methyl benzoate was performed in the lab:

Procedure below:

1. Prepare and ice bath in a 100mL beaker on a magnetic stir plate.

2. To a clean, dry 25 mL Erlenmeyer flask, add 1.0 mL of methyl benzoate via pipet.

3. Calculate the mass of methyl benzoate.

4. To the methyl benzoate, add 2.25 mL of concentrated (18M) sulfuric acid and a spin bar.

5. Carefully clamp the flask so that it is immersed in the ice bath and begin stirring.

6. Prepare the nitrating solution by adding 0.75mL of concentrated (18M) sulfuric acid and 0.75mL of concentrated (16M) nitric acid to a clean, dry vial.

7. Cool the mixture in a second ice bath.

8. With a Pasteur pipet, slowly add the cooled sulfuric acid-nitric acid solution to the stirred solution of methyl benzoate. *Addition should take approximately 15 minutes. Adding the nitrating agent more rapidly will increase the amount of by-products and decrease the yield

9. After all of the nitrating agent has been added, carefully remove the ice bath.

10. Continue stirring until the reaction has come to room temperature.

11. Then let the reaction flask stand undisturbed for 15 minutes.

12. Place 10 g of ice in a 100mL beaker.

13. With a Pasteur pipet, carefully transfer the reaction mixture to the beaker.

14. Rinse the flask with 5mL of cold water.

15. When the ice has melted, vacuum filter the crude crystals using a Buchner funnel.

16. Wash the crystals with 2 5mL portions of cold water and finally with 2 1.5mL of cold methanol.

17. The crude product can be recrystallized from methanol.

18. Record the mass of the dry product and calculate the yield.

QUESTION: What is the major product formed in this reaction? Justify your reasoning..

Melting point of the product was ranged from 97-102*C what is the major product formed?

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.

CHEM 1111 Lecture Notes - Lecture 4: Litmus, Tare Weight, Watch Glass

Document Summary

Get access

Related textbook solutions

Chemistry: Structure and Properties

Basic Chemistry

Principles of Chemistry Molecular Approach

Chemistry: Structure and Properties

Principles of Chemistry Molecular Approach

Chemistry: A Molecular Approach

Chemistry: A Molecular Approach

Principles of Chemistry: A Molecular Approach

Chemistry: The Central Science

Related Documents

CHEM 1111 Lecture Notes - Lecture 6: Graduated Cylinder, Hydroquinone, Fume Hood

CHEM 1111 Lecture Notes - Lecture 6: Graduated Cylinder, Hydroquinone, Fume Hood

CHEM 1111 Lecture Notes - Lecture 4: Tare Weight, Bunsen Burner, Inta

Related Questions