Recrystalization Lab by Thomas Nguyen [Student FVHS]

Pre-Lab Discussion

17cutm188 — 2013-11-14 21:16:46 UTC

Recrystallization is one way of isolating an ionic compound from a solution. If several ionic compounds are present in an aqueous solution, then a precipitation reaction may be performed to remove the unwanted ions. In this experiment, a known amount of NaCl will be dissolved in some water, and then recrystallized by boiling off the water.

Purpose: You Will Learn To

17cutm188 — 2013-11-14 21:17:19 UTC

To perform and master a recrystallization of an ionic compound

To write a procedure for a simple experiment

To calculate for percent error in an experiment

To understand how results affect percent error

To identify sources of error in experiments

Materials

17cutm188 — 2013-11-14 21:18:35 UTC

NaCl. Use a mass of about 1-2 grams.

Several pieces of glassware

Heating plate

Electronic balance

Water. Use about 25 mL

Tommy Nguyen. Tan Cu. Alex Faris. Miles Wilkerson

17cutm188 — 2013-11-14 21:20:37 UTC

Period

Materials

17friasac151 — 2013-11-14 21:27:44 UTC

Breakers

Watch glass

Rubber thong

Flask

Cylinder

Heating Plate

17friasac151 — 2013-11-14 21:28:06 UTC

Trial 1

17nguyentt101 — 2013-11-15 21:26:28 UTC

Trial #1

A.	Mass of salt (NaCl) used. Must be between 1 and 2 grams.	1.37g
B.	Mass of empty beaker before you start	162.41g
C.	Mass of beaker with recrystallized NaCl	163.68g
D.	Mass of recrystallized NaCl (C minus B)	1.27g
E.	Volume of water added to dissolve NaCl	25ml

Percent Error= 7.29 I think we got this percent error because some of the salt was spilled while we were measuring the recrystalized salt in the beaker.

Data

17nguyentt101 — 2013-11-18 21:22:21 UTC

Create a data table that will include all the masses and volumes that you have measured in the experiment. Make sure there is a data table for each trial.
Examples: mass of empty beaker, mass of NaCl before experiment, mass of NaCl after experiment, volume of water used, etc.
If you do more than 1 trial, please include the results for each trial. Use 1 table for each trial.

Trial 2

17nguyentt101 — 2013-11-18 21:43:23 UTC

A.	Mass of salt (NaCl) used. Must be between 1 and 2 grams.	1.16g
B.	Mass of empty beaker before you start	268.80g
C.	Mass of beaker with recrystallized NaCl	268.99g
D.	Mass of recrystallized NaCl (C minus B)	0.99g
E.	Volume of water added to dissolve NaCl	25ml

Percent Error= 14.65%

I think the reason why the percent is of because we probably didn't rinse all the salt out into the beaker. Also, I think the salt got blown away when the lid was partly open.

Conclusion

17friasac151 — 2013-11-19 21:16:20 UTC

1. Equation...(see Trial 1 and 2)

2. If our percentage was a negative, then we've must gotten more salt into our solution.

3. If our percentage was a postive, then we've must lose some salt during our experiment.

4. Well, I think working together is really important within a group project. Since we need to communicate to with our partners, then we need to communicate with others and work well with them in order to finish the project. Working together is the key to finishing a group project

17nguyentt101 — 2013-11-21 02:06:56 UTC

Steps

17cutm188 — 2013-11-21 05:27:29 UTC

1. We sent someone from the group to measure all the components. (Beaker and salt solution)

2. We heat up the heating plate, and while we wait, one of out member mix the salt water

3. We have Tommy set the salt solution onto the heating plate and now we wait for the solution to evaporate

4. Now the water has all evaporated, we set it to the side to cool down.

5. After that, we measure the recrystalized salt

6. Next, we subtract the original beaker with the beaker with salt in it.

7. Then we just plug into the equation of---- Accepted-experiment divided by accepted and times 100. Then we get our percent error.