Homework answers / question archive / Assignment #9 :Note:  Change any “0” value in your student number to a “7”

Assignment #9 :Note:  Change any “0” value in your student number to a “7”

Chemistry

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Assignment #9 :Note:  Change any “0” value in your student number to a “7”.

 

If b ≥ 7, x = 9                                               If d ≥ 7, y = 5

If b ≥ 4, x = 8                   If d ≥ 4, y = 4    

If b ≥ 1, x = 7

x

If d ≥ 1, y = 3

y

Dilutions                  

1. How much of a x.e % (w/v) stock solution is required to create 20.0 mL of a y.i % (w/v)

solution?                                                                                                                                        [3 marks]

 

 

 

 

 

 

 

 

 

 

                     

2. What is the final concentration of a solution if x.e mL solvent is added to y.d mL of a b.c M

solution?                                                                                                                                        [4 marks]

 

 

 

 

               

       

3. How much solvent must be added to b.c mL of a 34.6 % (v/v) stock solution to create at c.d %

(v/v) solution?                                                                                                                [4 marks]

 

 

 

 

 

 

 

 

 

 

Serial Dilutions            

4.  What is the initial concentration of a solution that has a final concentration of 0.dg % (w/v) that has been serially diluted 1/b, then 1/c, then finally 1/d?  (3 SD)                                    [5 marks]

             

 

 

 

 

 

 

 

 

 

               

 

5.

You have a

n aliq

uot

of

cells

with a

co

ncentrat

ion of

f

.

h

i

x 10

x

cells/mL.

P

re

pare a serial di

lution

to create

e

.

f

mL

w

ith a

c

oncentration of

c

.

de

x

10

y

cells/mL.

 

Include your plan to accurately create this serial dilution.  Include all the volumes of solute,

solvent, and total solution.                                                                                                       [10 marks]

 

               

Standard Curve

You collect the following data from a Spectrophotometer.                                                              [2 marks]

Concentration (mg/mL)	% Transmittance	Absorbance
0.0	100
0.625	93.7
1.25	87.6
2.5	76.6
5.0	57.8
10.0	33.7
20.0	11.2
Unknown	cd.e

 

?? = 2 − log (%??)

 

6. Using graph paper, create a handwritten Standard Curve.                                   [10 marks]

Ensure it is properly labeled and professional in appearance.

Using the % Transmittance data for the Unknown to determine the concentration.

 

7. Using Microsoft Excel, create a table of values and a Standard Curve digitally.               [10 marks]

Using the equation from the Line of Best Fit, determine the concentration of the Unknown.

Submit a professional looking Table and Standard Curve.

 

8. Calculate the Percent Error for the Unknown, using the digital data as Accepted Value.  (2 SD)

         [2 marks]