Ch4 Lec 8 - Revision history

Bes: /* Dilution Worksheets */

2020-03-25T16:48:39Z

Dilution Worksheets

2020-03-25T16:47:52Z

Dilution Worksheets

2020-03-25T13:37:11Z

Dilutions

2020-03-25T13:04:40Z

2020-03-20T16:23:53Z

Processing this Data

2020-03-20T16:19:28Z

Dilution Activity

2020-03-20T16:18:05Z

Processing this Data

2020-03-20T16:11:25Z

Processing this Data

2020-03-20T16:09:45Z

Dilution Activity

2020-03-20T16:08:50Z

Dilution Activity

@@ Line 19: / Line 19: @@
 ===Dilution Worksheets===
-The following worksheets were originally planned as a pre-lab activity. I suggest that you look these [http://esr.monmsci.net/wiki/images/a/ab/Prelab_Molarity_dilutions.pdf Concentration, Molarity, and Dilutions worksheets] over and to confirm your understanding, there is a WA; HW4.3 spring 2020 (Dilutions)...see WA fro due date.
+The following worksheets were originally planned as a pre-lab activity. I suggest that you look these [http://esr.monmsci.net/wiki/images/a/ab/Prelab_Molarity_dilutions.pdf Concentration, Molarity, and Dilutions worksheets] over and to confirm your understanding, there is a WA; HW4.3 spring 2020 (Dilutions)...see WA for due date.
 ===Dilution Activity===

@@ Line 19: / Line 19: @@
 ===Dilution Worksheets===
-The following worksheets were originally planned as a pre-lab activity...i did not reformat them for these "lecture notes."
+The following worksheets were originally planned as a pre-lab activity. I suggest that you look these [http://esr.monmsci.net/wiki/images/a/ab/Prelab_Molarity_dilutions.pdf Concentration, Molarity, and Dilutions worksheets] over and to confirm your understanding, there is a WA; HW4.3 spring 2020 (Dilutions)...see WA fro due date.
 ===Dilution Activity===

← Older revision		Revision as of 13:37, 25 March 2020
Line 1:		Line 1:
	===Dilutions===		===Dilutions===
		+	Sec 4.5 : after Molarity...Dilutions of Solutions
		+
		+	When doing dilutions you need to keep in mind the ''number of moles'' that are being moved from one place to another. A typical dilution problem involves taking a certain volume of a solution of known molarity and then "diluting" this to a new volume. So if i have a solution of a molarity 1.23 M or 1.23 moles/L and i remove 0.0100 L of it, then i will have taken out a certain number of moles:
		+
		+	::: 1.23 moles/L * 0.0100 L = 0.0123 moles
		+
		+	Now if these moles are diluted to a volume of 0.200 L, then the new concentration will be:
		+
		+	:::0.0123 moles/0.200 L = 0.0615 moles/L or 0.615 M
		+
		+	Since the number of moles removed from the original solution is the same as the number of moles in the final diluted solution, there is a shortcut to this calculation using:
		+
		+	:::M<sub>1</sub>V<sub>1</sub> = M<sub>2</sub>V<sub>2</sub>
		+
		+	In the above calculation, M<sub>1</sub> = 1.23 M, V<sub>1</sub> = 0.0100 L, V<sub>2</sub> = 0.200 L and we are asked to determine M<sub>2</sub>...so,
		+
		+	:::1.23 M * 0.0100 L = 0.200 L * M2 or M2 = (1.23 M* 0.0100 L)/0.200L ---> M2 = 0.0615 M

	===Dilution Worksheets===		===Dilution Worksheets===

← Older revision		Revision as of 13:04, 25 March 2020
Line 1:		Line 1:
−	~~Don't read ahead :), this lecture is not yet complete.~~
−
	===Dilutions===		===Dilutions===

← Older revision		Revision as of 16:23, 20 March 2020
Line 25:		Line 25:

	<div align="right"> Answer --> [blue dye]<sub>sports drink</sub>= 0.025 M </div>		<div align="right"> Answer --> [blue dye]<sub>sports drink</sub>= 0.025 M </div>
−		+	:3) Make sure your graph has axis labels, and a text box with your name and email me a screenshot of your graph...if you don't know how to take a screenshot (MAC command-shift-3 or command-shift-4, PC use app Snip-it).
−	~~[https~~:~~//youtu~~.~~be/AN4KifV12DA Crash Course Video]~~

@@ Line 16: / Line 16: @@
 [[File:Screen Shot 2020-03-20 at 10.47.22 AM.png|400px]]
-If the [blue dye solution 1] = 0.01 M, [blue dye solution 2] = 0.02 M, [blue dye solution ] = 0.03 M (these are referred to as your "standards"), and solution 1 absorbance is 0.2, solution 2 absorbance is 0.4, solution 3 absorbance is 0.6,  AND the sports drink  absorbance is 0.5, then you can process this data as described below to determine the concentration of the blue dye in the sports drink.
+If the [blue dye solution 1] = 0.010 M, [blue dye solution 2] = 0.020 M, [blue dye solution ] = 0.030 M (these are referred to as your "standards"), and solution 1 absorbance is 0.20, solution 2 absorbance is 0.40, solution 3 absorbance is 0.60,  AND the sports drink  absorbance is 0.51, then you can process this data as described below to determine the concentration of the blue dye in the sports drink.
 ====Processing this Data====

@@ Line 22: / Line 22: @@
 :2) Go to Excel (or by hand) and make a graph of concentration (x-axis) vs. absorbance (y-axis) for the standards...do not include the sports drink absorbance in this plot.
 ::- fit a trendline to the data, showing the equation on the graph, note the equation in your notes.
-::::''Your trendline equation is in the form of y= m*x + b, or Abs = m*Concentration + b, where b should be 0., there for Abs = m*Concentration. The value for m (or the slope) is the conversion factor between the absorbance and concentration. NOW...plug in the absorbance for the sports drink into your trendline equation and then solve for the concentration:''
+::::''Your trendline equation is in the form of y= m*x + b, or absorbance = m*concentration + b, where b should be 0, therefore, absorbance = m*concentration. The value for m (or the slope) is the conversion factor between the absorbance and concentration. NOW...plug in the absorbance for the sports drink into your trendline equation and then solve for the concentration:''
 [https://youtu.be/AN4KifV12DA Crash Course Video]

@@ Line 10: / Line 10: @@
 A lab was originally planned but is now being used as a class activity. In this activity/lab, you were going to determine the concentration of the blue dye found in a "blue" PowerAde sports drink.
-[[File:Screen Shot 2020-03-20 at 11.08.25 AM.png|200px]]
+<div align="center">[[File:Screen Shot 2020-03-20 at 11.08.25 AM.png|50px]] </div>
 Although the many details associated with the lab are outlined in the [http://esr.monmsci.net/wiki/images/8/86/Lab_Molarity_dilutions.pdf Molarity Lab], the basic take home message is...if you make a set of 3 solutions/dilutions of the blue dye and you use a spectrophotometer to measure how much light is absorbed by the solution (aka, the "absorbance") then you can generate a set of data to complete the following table: