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Methodical guidance for laboratory work №1

SEMEY STATE MEDICAL ACADEMY

Methodical recommendation for the laboratory lesson

Specialty: 0501301General medicine

Discipline: chemistry

Chair: of chemistry and technology of medicine

Higher base medical education, course – 1

Topic №8: Peculiarities of HMC solutions. Viscosity of HMC solutions. Swelling. Quiz#2-Midterm examination.

Semey 2007

Approved

on the chair meeting from “_____”____________2007.

Protocol № ____

Head of the chair of chemistry and technology of medicine,

prof. __________ Gavrilenko I.V

1.Topic №8: Peculiarities of HMC solutions. Viscosity of HMC solutions. Swelling. Quiz#2-Midterm examination.

2.Aim: to study properties of solution HMS, peculiarities of nature of intermolecular interaction in HMS solution..

Quiz#2-Midterm examination (lessons 5-8)

3.Objectives of teaching: to teach influence of different factors on swelling processes. Relate properties of solution HMS with processes occurring in living organism

4. Basic questions:

1. HMS, its classification. Methods of receiving HMS (polymerization, polycondensation) ВМС, их классификация. Методы получения ВМС (полимеризация и поликонденсация). For examples. Biopolymers.

2. Structure and form of HMS molecule.

3. Polyampholytes. (polyelectrolyte). Isoelectric point. Properties of protein in isoelectric point.

4. Swelling and dissolving of HMS. Mechanism of swelling.

5. Coagulation of HMS. Types of coagulation.

Methods of teaching:

The determining initial level knowledge’s of student on chemistry. The conversation and questioning on topic of the lesson. Fulfilling the laboratory work and protection of the report. Midterm examination – 5-8 lessons.

Methodical guidance for laboratory work №1

Experiment №1. Heat evolving by swelling

1. pour in the test-tube 5ml of water measure its temperature

2. put there l g of starch and dip the thermometer in this test-tube and measure its temperature

3. compare temperature before and after starch dissolution explain what you saw and make a conclusion.

Experiment №2. Protein precipitation by boiling in acidic medium

Pour in two test-tubes 2ml of protein precipitation & solution. Pour in the 1st t-t 1 drop of acetic acid. Boil both of the test-tubes. Watch the quick precipitation of the protein in the 1st test-tube because the protein in this t-t is in IE state.

Experiment 3: Salting out of the protein by ammonium sulfate

Pour in the test-tube 2ml of 1% eg protein solution or gelatin and add saturated solution of ammonium sulfate drop by drop till precipitation of the protein and then add a little of distilled water. This process is reversible and by addition of water it is protein dissolution. Make conclusion.

Experiment 4. Determining of viscosity of HMS solution.

For study of viscosity diluted HMS solution used the methods, founded on measurement of speed of solution through capillary tubes depending on attached pressures. By the law Newton, volume to liquids, running through capillary tube per unit time, proportional attached pressure Р and back proportional factor of viscosity h:

V= К·Р/h

Constant K is characterize properties of the capillary, its depends on its lengths l and radius r. Operative power herewith is a difference of the pressures between both poles of the liquid.

Cinematic viscosity of solution is define by formula:

n = g/980,7·t·K

where: n - cinematic viscosity, sm/sec2.

t -time of the outflow to liquids, sec.

g - a speeding-up of gravity power, sm/sec2

K - a factor from passport to viscosity-meter (0,0608).

Order of the work with viscosity-meter.

For measurement of time of the outflow of liquids on outlet tube (6) put on the rubber hose. Further, having jammed finger knee (5) and crossover viscosity-meter, lower the knee (1) in container with liquid and trying up its before mark M2 reservoir, keeping a check on that to in liquids was not formed bubbles of the air.

In that moment, when level of liquids will reach mark M2, viscosity-meter take out of container and quickly turn over in normal position. Take out of outer face end knee (1) excess of liquids and put on rubber tube on it.

Viscosity-meter install in thermostats so that reservoir (2) was below level to liquids in thermostats. After endurance in thermostats not less 15 minutes under given temperature trying up the liquid in knee before one third of the height of the reservoir (2). Report the knee (1) with atmosphere and define time of letting down before mark of liquids from mark M1 before M2.

Viscosity calculate on formula: n = g/980,7·t·K, on average (from several measurements) of time of the outflow of liquids.

The movement of the work.

Fill viscosity-meter of investigation liquid. On stopwatch note time, necessities for outflow through capillary of the volume between mark M1 and M2. Define time of the outflow for solution 2-3 times and take the average value. Cinematic viscosity define on formula:

n = g/980,7·t·K

Make a conclusion.

At the end of the work to wash the capillary viscosity-meter several times by distilled water.

6.Literature:

1. J. M. Sehgal. Modern Chemistry, class XI, Delhi, 1989 - 15 items.

2. Jean B. Umland & John M. Bellama, General Chemistry. Houston. USA. 1996 - 1 item.

3. Darrel D. Ebbing, General Chemistry, Wayne University, USA. 1990 - 3 items.

4. Karen C. Timberlake, Chemistry - An Introduction to General. Organic and Biochemistry, Los Angeles, USA, 1991-1 item.

7.Control:

№1.A protein has isoelectric point рН =2. Indicate by which value of pH degree of swelling and rate of gelatination will have:

а) maximal, б)minimal?

рН1 = 1,8; рН2= 2,0; рН3 = 5,0; рН4= 3,0

№2. A protein of milk has isoelectric point рН =4,6. Indicate by which value of pH rate of precipitation and rate of electrophoreses of this protein will have:

а) maximal, б)minimal?

1) рН = 4,6 2) рН= 1,0 3) рН= 5,0 4) рН= 4,2

№3. What changes of properties and structure of proteins occur at denaturising?

№4. Name the high molecular substance of organism. What kind of monomers are they formed?

№5. Change, what parameter increases the velocity of hardening of HMS?

№6. Action, what factor decreases the degree of coagulation HMS?

№7.Why solutions some HMS possess anomalous high viscosity?

№8. What pressure called “oncotic pressure”?


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