Posted by **Chris** on Monday, October 9, 2006 at 12:13pm.

In a lab we are trying to find the percent yield of NaCl collected after evaporating the water off an NaCl solution. We made up a .100 M NaCl solution, and used 10. mL of it in our experiment.

We know that the empty evaporating dish and cover mass 68.9132 +/- .0003 g, and after our final trial our evaporating dish, cover, and NaCl mass 68.9695 +/- .0003 g.

We calculated our theoretical yield as such..

10. mL +/- .2% x (.100 sub 0 mol +/- .6 % / 1 L) x ( 1 L/ 1000 mL) x (58.77 g / 1 mol) = .058 +/- .001 g

I calculated our actual yeild as such..

68.9695 +/- .0003 g -> 68.9695 +/- .0004 sub 3 %

- 68.9132 +/- .0003 g -> 68.9132 +/- .0004 sub 4%

= .0563 +/- .00008 sub 7 %

Going by these calculations, I calculate the percent yield to be

(.0563 +/- .0008 sub 7 %) / (.058 +/- 1.sub 7 %) = 97 +/- 2 (absolute) %

However, my partner got 97 +/- 3%, and since I haven't done error calculations in a while I'm trusting that her answer is correct. Can someone help me find what I did wrong?

I get one percent error on the measured mass, and two percent on the theoretical.

Stick with your three percent. The precision of the known solutions (molarity and volume) as you have cited is beyond what most college labs do.

## Answer This Question

## Related Questions

- Chemistry - In a lab we are doing, we need to find the theoreical amount of NaCl...
- chemistry - In a laboratory experiment, a 18.0 ml sample of NaCl solution is ...
- chemisrty - Q4) Suppose you prepare 950 mL of a solution by dissolving 100 grams...
- chemistry - a solution is made by dissolving 25 g NaCl in enough water to make 1...
- Chemistry - A solution is made by dissolving 0.100 mol of NaCl in 5.35 mol of ...
- Chemistry - I am trying to find the theoretical yield for this lab I am working ...
- college chemistry - a solution is made by dissolving 25 g NaCl in enough water ...
- Chem - I am doing a lab concerning pH... Why is it necessary to allow a mixture ...
- Scient - (NaCl) solutions used in intravenous injections have a concentration ...
- bio - You have a sample of NaCl that contains 100 mg/ml NaCl. You are trying to ...

More Related Questions