Transcript Mass/Volume Concentration Equation

Unit 3: Laboratory
Procedures
Today: 10/24/2013
• Turn to page 45 in your lab manual and briefly read over the
background section.
• Pay attention to Mass/Volume Concentration Equation
• For your background section include:
 A brief description of a spectrophotometer
 How this instrument works
 What it detects
 Define solvent and solute, and mention the most
common solvent used in laboratories.
Today: 10/31/2013
• Gummy Bear Sacrifice: Exothermic Reactions, Sugar
Metabolism, Generally Awesome
• Flaming Jack: Boric Acid & Fluorescence
• Rock Candy: Super Saturation of a liquid using heat
• Dry Ice Bubbles: Surface tension & Sublimation
Today: 10/25/2013
1. Fill a small test tube with deionized water (do this now!).
2. What is a spectrophotometer & how does it work?
3. We will be testing our samples using a percent
transmission setting on our specs. What does this mean?
4. How many grams would it take to make 7 mL of solution at
a concentration of 425 mg/ml?
5. If I add three mL of water to the above solution, what is the
new concentration of the solution?
Bellwork: 10/28/2013
1. What are the steps for using a spectrophotometer?
2. What is the equation for determining mass/volume
concentration when preparing a solution?
Today: 10/29/2013
1. You will complete the solution preparation & spec practice lab (pages
45-49).
2. Clean up all the equipment that you used. Please use the sinks
available in the Pre-AP Chem Lab
3. For your data analysis section, compare your absorbance values with
those of two other groups. Explain why they values are similar/different.
4. For your conclusion:
1. Answer the Thinking Like a Biotechnician questions on page 48.
2. Answer the question posed in Procedure step #4.
3. Include a brief description of possible errors.
4. Answer the questions on page 49. Ignore 11, 13, 15, and 17.
Today: 10/30/2013
1. For the Background:
• Include all of the equations that you will need for this lab.
• Give an example of each equation being used in a practical setting.
• No “problem” is needed for this lab.
• The “safety” section needs to be detailed for this lab
2. This lab will cover pages 50 – 54 in the lab notebook.
Today: 10/30/2013
1. Starting on page 51:
1. Do the steps 1 and 2 for Part 1/2/3. If you are unable to confirm
your math with another group, check with me.
2. Make sure you show your work.
Bellwork: 11/01/2013
1. 330 mL = _________ L
_______________
2. P-10/20/100/1000 measure what volumes?
Today: 11/01/2013
1. You must complete the following before the end of class, and your work
must be initialed by me to receive full credit for the lab:
a) Page 51 in the lab manual – Complete parts 1 and 2.
b) Page 51 through 53 in the lab manual – Please read over part 3, 4,
and 5 and draw the data tables for these parts in your lab
notebook.
• Parts 3, 4, and 5 are not complicated procedures, but they will take
most of the class on Monday to complete.
2. I need a lot of help cleaning up my lab. If you finished today’s work, I
would really appreciate the help cleaning up our lab space.
Today: 11/04/2013
1. How would you calculate the mass required to make the following
solutions:
•
5 mL of 2.5% glucose solution:
•
2000 mg = ___________g
•
5L = ___________mL
•
6.3cm = _________mm
Today: 11/05/2013
Don’t wait for me to tell you to get started, get to work!
1. You should be able to complete all of your lab work today.
2. You will have time in class tomorrow to work on finishing your lab
notebook work.
**Addition for your lab instructions – The spec will be set at 540 nm, not
590 nm
Today: 11/04/2013
Changes to the lab:
1. You will make two gelatin solutions of each concentration.
2. You will run the experiment twice, once using your homemade Biuret
Reagent, and a second time using a store-bought Biuret Reagent.
3. For your conclusion you must answer all of the questions presented in
the “Data Analysis/Conclusion” section of your lab manual, all “Thinking
Like a Biotechnician” questions, and all math questions on page 54
except 11, 13, 15, 17, and 19.
Today: 11/07/2013
You need to complete the lab and the notebook portion of your lab today. I
will collect your lab notebooks at the end of class!
Changes to the lab:
1. You will make two gelatin solutions of each concentration.
2. You will run the experiment twice, once using your homemade Biuret Reagent, and
a second time using a store-bought Biuret Reagent.
3.
For your conclusion you must answer all of the questions presented in the “Data
Analysis/Conclusion” section of your lab manual, all “Thinking Like a Biotechnician”
questions, and all math questions on page 54 except 11, 13, 15, 17, and 19.
**Addition for your lab instructions – The spec will be set at 540 nm, not 590 nm
Using the Spec:
1. Turn the instrument on and allow it to warm up for 15
minutes.
2. Set your spec to the desired wavelength.
3. Use a kim wipe to clean off any finger prints, oil, debris,
etc., from the outside of your test tube.
4. Insert the standard test tube (deionized water) and blank
the spec.
5. Insert your test sample and read/record both
%transmittance and absorbance.
6. Repeat steps 4 and 5 for each testable sample.
A) Metric System

IS: International system of measurement
Prefix
Symbol
Factor
kilo
hecto
k
h
1000
100
(base unit) no prefix
----
1
deci
centi
d
c
0.1
0.01
milli
micro
nano
m
µ
n
0.001
0.000 001 (10-6)
0.000 000 001 (10-9)
A) Metric System
A) Metric System

To easily convert between
prefixes we can use the BS
rule
B) Measuring Volumes
The main units we measure volumes in are
microliters, milliliters and liters
1000 µL = 1 mL = 0.001 L
 *know these conversions!!!!!
 Practice:

1)
2)
3)
4)
125 mL = _________
125,000 µL
33 mL = _________
L
0.033
4 L = _________
mL
4,000
200 µL = _________
mL
0.200
C) How do we measure
volume in the lab?



Graduated cylinder: Measure more than 10 mL
Pipet: measure between 0.5 mL &10 mL
Micropipet: less than 1 mL
C) How do we measure
volume in the lab?

1)
2)
3)
4)
Given the following volumes, what
instrument would you use to measure that
volume:
100 mL Graduated Cylinder
25 mL Graduated Cylinder
5 mL Pipet
10 mL Pipet or
Graduated Cylinder
5)
6)
7)
8)
100 µL Micropipet
25 µL Micropipet
0.005 mL Micropipet
56 mL Graduated
Cylinder
D) How to use a pipet

Draw this:

In order to use a pipet you much also have a
pipet pump:



Blue: 1- and 2-mL pipets
Green: 5- and 10-mL pipets
Red: 25- and 50-mL pipets




Roll the gear so the top raises, this will draw up the
liquid into the pipet
Roll the gear the opposite direction to expel the liquid
DO NOT push the top of the pipet pump – this may
break the pump
When selecting a pipet to use remember to use the
smallest pipet as possible to be as precise as
possible
E) How to use a micropipet
Used to measure amounts less
than 1 mL
 3 sizes of pipets:

P10 0.5 µL to 10 µL
 P100 10 µL to 100 µL
 P1000 100 µL to 1000 µL


Each micropipet has only a
certain amount of precision

Make sure you pay attention to this!
E) How to use a micropipet
These are the
readings for
micropipets
 Main difference
between 20 and 10
is the top limit, it still
has the same unit
places on the
display

E) How to use a micropipet

P10/P20
E) How to use a micropipet

P100/P200
E) How to use a micropipet

P1000/P2000
F) Making Solutions
One of the most essential skills
 Labs often buy the solid form of a compound
because it is often cheaper and many times
multiple concentrations are used.
 Almost all reactions involving proteins and
nucleic acids occur in an aqueous solutions.
 Solution contains 2 parts:

Solute – what is being dissolved
 Solvent – what us doing the dissolving

F) Making Solutions

To prepare a solution:
1.
2.
3.
4.
Measure out solid mass of solute needed
Add solid to container with a little water
Dissolve solid
Add enough water to reach desired volume
Today: 11/11/2013
We will review last week’s labs and discuss
molarity
 Clean up day (hooray…)!
 Short metric conversion assignment

G) Concentrations

A measure of how many particles are in a
certain volume
Common Units of Concentration
Concentration
Common Units of Measurement
mass/volume
g/L, mg/mL, µg/mL, µg/µL
% mass
%
Molarity
M (mol/L), mM (mmol/L), µM (µmol/L)

Normality made be used for acids & bases only
H) Preparing Mass/Volume
Concentration
Mass/Volume Concentration Equation
Conc. desired x volume desired = mass of solute
(g/mL)
(mL)
(g)
Example: How do you prepare 100 mL of 0.05 g/mL
solution of hemoglobin?
1) Use the equation to determine mass of solute.
0.05 g/mL x 100 mL = 5 g hemoglobin
2) Give directions for making solution:
Measure out 5 g of hemoglobin and pace into a 100 mL
flask, add about 10-20 mL of dH2O. Dissolve all hemoglobin
then add enough water to make 100 mL of solution.
H) Preparing Mass/Volume
Concentration
Mass/Volume Concentration Equation
Conc. desired x volume desired = mass of solute
(g/mL)
(mL)
(g)
Practice: How do you prepare 150 mL of 2 mg/mL gelatin?
1) Use the equation to determine mass of solute.
2 mg/mL x 150 mL = 300 mg gelatin = 0.3 g gelatin
2) Give directions for making solution:
Measure out 0.3 g of gelatin and dissolve in a little bit of
water. Add enough water to make 150 mL of solution.
I) Preparing % Mass/Volume
Concentration
% Mass/Volume Concentration Equation
Convert % to decimal
Decimal % x volume desired = mass of solute
(g/mL)
(mL)
(g)
Example: How do you prepare 50 mL of 10% NaCl solution?
1) Use the equation to determine mass of solute.
10% → 0.10 g/mL
0.10 g/mL x 50 mL = 5 g NaCl
2) Give directions for making solution:
Measure out 5 g of NaCl and dissolve in a small amount of
water. Add enough water to make 50 mL of solution.
I) Preparing % Mass/Volume
Concentration
% Mass/Volume Concentration Equation
Convert % to decimal
Decimal % x volume desired = mass of solute
(g/mL)
(mL)
(g)
Example: How do you prepare 60 mL of 10% glucose?
1) Use the equation to determine mass of solute.
10% → 0.10 g/mL
0.10 g/mL x 60 mL = 6 g glucose
2) Give directions for making solution:
Measure out 6 g of glucose and dissolve in a small amount of
water. Add enough water to make 60 mL of solution.
J) Preparing solutions
using Molarity
Molarity Units: mol/L
 mole = the number of particles in a
substance that is equal to the mass (in
grams) on the periodic table
58.5 g
 Ex: 1 mole NaCl = _____

1 mole Na = 23.0 g
1 mole Cl = 35.5 g
1 mole NaCl = 23.0 g + 35.5 g = 58.5 g

1 mol of any substance will not be the same
as a different substance!
J) Preparing solutions
using Molarity

Practice: Solve the following.
180.0
1) 1 mol C6H12O6 = ________
g
(12.0 x 6) + (1.0 x 12) + (16.0 x 6)
2)
111.1
1 mol CaCl2 = ________
g
(40.1 x 1) + (35.5 x 2)

180.0g and 111.1g are called the molecular
weight (MW) or formula weight of its
substance
J) Preparing solutions
using Molarity
Molarity Concentration Equation
Volume wanted x molarity x MW = mass of solute
(L)
(mol/L)
(g/mol)
(g)
Example: How many grams are needed to make a 75 mL
solution of 2M CaCl2?
0.075 L x 2M x 111.1 g/mol = 16.67g CaCl2
Practice: How do you prepare 20 mL solution of 0.25 M NaCl?
0.020 L x 0.25M x 58.5 g/mol = 0.293 g NaCl
Measure out 0.293g of NaCl and dissolve in enough water
to make 20 mL of solution.
Bellwork: 11/12/2013

What mass of calcium chloride (CaCl2) is
needed to make 125 mL of 0.55 M CaCl2
solution?
Bellwork: 11/12/2013
What mass of calcium chloride (CaCl2) is
needed to make 125 mL of 0.55 M CaCl2
solution?
 1st convert 125 mL into L (molarity =
moles/liter)
 125 mL = 0.125 L
 Then use the molarity concentration
equation

Bellwork: 11/12/2013
Volume wanted x molarity x MW = mass of
solute
 0.125 L x 0.55 M CaCl2 x 111 grams/mole =
 7.63 grams of CaCl2 and add solvent up to
125 mL

K) Dilutions
Buying concentrated solutions can save
money
 If you need a very dilute solution starting
from a more concentrated solutions may be
required

K) Dilutions
Dilution Equation
C1V1=C2V2
C = Concentration
V = Volume
• 1 & 2 stand for different solutions
• Concentrations can be in any unit as long as both are
the same, same with volume
Example: How would you prepare 1 L of 1mg/mL protein
solution from 100mg/mL concentrated stock?
C1= 1 mg/mL
V1=1L
C2=100 mg/mL
V2=?
(1 mg/mL)(1L) = (100 mg/mL)(V2)
V2=10mL
Measure out 10 mL of protein stock solution and mix in
enough water to make 1 L of solution.
K) Dilutions
Dilution Equation
C1V1=C2V2
C = Concentration
V = Volume
• 1 & 2 stand for different solutions
• Concentrations can be in any unit as long as both are
the same, same with volume
Practice: How do you make 200 mL of 10mM CaCl2 from
75mM CaCl2 solution?
C1= 10 mM
V1= 200 mL C2=75 mM
V2=?
(10 mM)(200mL) = (75 mM)(V2)
V2=26.6mL
Measure out 26.6 mL of CaCl2 and mix in enough water to
make 200 mL of solution.
Get to Work!


Changes to the Lab:
 Step 3 (page 56) – You do NOT need to graph your
data. The trend(s) should be obvious through a data
chart.
For your conclusion:
 Possible errors
 Results with evidence
 Practical use for this technique
 Thinking like a Biotechnician, questions 1, 2, 3
 A summary of page 58 – why is pH biologically
important? Etc.
Get to Work!

For your background section:
•
•
•
Explain: mole, molarity, Avogadro's number, and
molecular weight
Write out the molarity concentration equation
(include all units)
Solve the following, showing all of your work:
•
•
What is the molarity of a solution containing 9.478
grams of RuCl3 in enough water to make 1.00 L of
solution?
How many grams of KMnO4 are required to prepare
1.0 L of a solution of 1.5 M KMnO4?
Get to Work!

For your background section:
•
•
•
Explain: mole, molarity, Avogadro's number, and
molecular weight
Write out the molarity concentration equation
(include all units)
Solve the following, showing all of your work:
•
•
What is the molarity of a solution containing 9.478
grams of RuCl3 in enough water to make 1.00 L of
solution?
How many grams of KMnO4 are required to prepare
1.0 L of a solution of 1.5 M KMnO4?
Today: 11/15/2013
You must:
1. Complete Lab 3g, pages 55-57
2. Clean Up your equipment from yesterday
(everything can go down our lab sink)
3. Turn in your lab notebook before you leave

Today: 11/18/2013
Lab 3h (page 59)
 Plan on taking the exam for this unit on
Friday. The exam will focus on pages 31 –
62 in the lab manual. The lab will consist of
written and practical questions.

Today: 11/19/2013
Brief information about AAI National
Conference (immunology2014.org)
 Some groups still need to clean up from last
week
 A change in pace of labs
 You should be able to have about half of
your solutions made today.
 Don’t hog the analytical balances.

Today: 11/18/2013


Lab 3h (page 59)
Background expectations:
• What does it mean to dilute a solution. Why would this
be necessary in a laboratory setting?
• Write out & define the dilution equation
• What is a serial dilution? What type experiment would
use a serial dilution?
• Showing all your work, answer the following questions:
• Prepare 200 mL of 25 mg/mL NaOH solution from a
150 mg/mL NaOH
.
• 800 mL of 5X CuSO4 5 H2O solution from 25X
CuSO4 .5 H2O
Today: 11/21/2013

Address the cloudy solution issue







Everyone should have at least one set of absorbance data to graph
Only one graph will be required for your lab notebook
Hand out exam review sheets
Unit #3 Exam will be one Monday
Lab notebooks will be turned in Friday for grading
(hopefully)
Unit math/practical quiz will be on Friday
Turn in your AAI information sheets if you are interested in
going on the trip in May
Today: 11/21/2013

Changes to the lab & additions for conclusions:







Only one graph will be required (make sure all axis are labeled)
Do NOT do any of the “Diagram of How to Prepare It” questions (2,
4, 6, 8, 10, 12, 14)
Complete all Thinking Like a Biotechnician Questions
Explain your results, including the cloudiness issue, as well as what
you would have predicted to see in the absorbance without the
cloudiness problem
Possible error section
No Practical application section is needed, this will be answered
through the Thinking Like a Biotechnician Questions
Add: Do you think it would be beneficial to have this unit as our first
unit, including labs I skipped from pages 31-40. Explain why or why
not
Unit Equations:
Mass/Volume Concentration Equation
Conc. desired x volume desired = mass of solute
(g/mL)
(mL)
(g)
% Mass/Volume Concentration Equation
Convert % to decimal
Decimal % x volume desired = mass of solute
(g/mL)
(mL)
(g)
Unit Equations:
Molarity Concentration Equation
Volume wanted x molarity x MW = mass of solute
(L)
(mol/L) (g/mol)
(g)
•
Dilution Equation
C1V1=C2V2
C = Concentration
V = Volume
• 1 & 2 stand for different solutions
Concentrations can be in any unit as long as both are the same, same
with volume