Unit 3: Laboratory Procedures

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.


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: 11/07/2013You 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 measurementPrefix Symbol Factor

kilo k 1000hecto h 100

(base unit) no prefix ---- 1deci d 0.1centi c 0.01milli m 0.001

micro µ 0.000 001 (10-6)nano n 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) 125 mL = _________ µL2) 33 mL = _________ L3) 4 L = _________ mL4) 200 µL = _________ mL

125,0000.033

4,0000.200

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?

Given the following volumes, what instrument would you use to measure that volume:

5) 100 µL6) 25 µL7) 0.005 mL8) 56 mL

1) 100 mL2) 25 mL3) 5 mL4) 10 mL

Graduated Cylinder

Graduated Cylinder

GraduatedCylinder

Pipet

Pipet or Graduated Cylinder

Micropipet

Micropipet

Micropipet

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!


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


P10/P20

E) How to use a micropipet P100/P200


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. Measure out solid mass of solute needed2. Add solid to container with a little water 3. Dissolve solid4. 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

Normality made be used for acids & bases only

Common Units of ConcentrationConcentration Common Units of Measurementmass/volume g/L, mg/mL, µg/mL, µg/µL

% mass %Molarity M (mol/L), mM (mmol/L), µM (µmol/L)

H) Preparing Mass/Volume Concentration

Mass/Volume Concentration EquationConc. 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 hemoglobin2) 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


(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.

% Mass/Volume Concentration EquationConvert % to decimal

Decimal % x volume desired = mass of solute(g/mL) (mL) (g)

I) Preparing % Mass/Volume Concentration

Example: How do you prepare 50 mL of 10% NaCl solution?1) Use the equation to determine mass of solute.

0.10 g/mL x 50 mL = 5 g NaCl2) 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.

10% → 0.10 g/mL

I) Preparing % Mass/Volume Concentration



Example: How do you prepare 60 mL of 10% glucose?1) Use the equation to determine mass of solute.

0.10 g/mL x 60 mL = 6 g glucose2) 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.

10% → 0.10 g/mL

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

Ex: 1 mole NaCl = _____ g

1 mol of any substance will not be the same as a different substance!

1 mole Na = 23.0 g 1 mole Cl = 35.5 g

1 mole NaCl = 23.0 g + 35.5 g = 58.5 g

58.5

J) Preparing solutions using Molarity

Practice: Solve the following.1) 1 mol C6H12O6 = ________ g

2) 1 mol CaCl2 = ________ g

180.0g and 111.1g are called the molecular weight (MW) or formula weight of its substance

(12.0 x 6) + (1.0 x 12) + (16.0 x 6)

(40.1 x 1) + (35.5 x 2)

180.0

111.1

J) Preparing solutions using MolarityMolarity 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 NaClMeasure out 0.293g of NaCl and dissolve in enough water

to make 20 mL of solution.


What mass of calcium chloride (CaCl2) is needed to make 125 mL of 0.55 M CaCl2 solution?


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


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 EquationC1V1=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




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=26.6mLMeasure 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 55-572. 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:


(g/mL) (mL) (g)



Unit Equations:

Molarity Concentration EquationVolume wanted x molarity x MW = mass of solute

(L) (mol/L) (g/mol) (g)




Unit 3: Laboratory Procedures

Documents

lab work

lab notebook

lab space

labthis lab

lab manual complete

background section

glucose solution

todays work