Microscale Experiments in Microscale Experiments in Chemistry Chemistry

–The Need of the New Millenium–The Need of the New Millenium

Newer Ways of teaching Laboratory Courses with New Apparatus

Group 5Elwyna Malambut

Introduction

• Chemistry has always been an experimental science-and desired in teaching of every chapter of chemistry

• Lapse because of large- scale operation of experiments

Students perform the test on a large scale involving cumbersome assemblies of apparatus and huge amounts of chemicals in laboratories. Effects: •Difficult to dispose products, excess reagents and solvents without harming the environment

• Lab are stocked with huge flasks, big bottles with toxic gases and vapors of chemicals- a health hazard in lab (teachers, students and laboratory staffs)

• Increasing number of students, and consumption of chemicals and glassware add a heavy charge on the budgets of the running the practical classes

Newer Ways of teaching Laboratory Courses

• In 1993, microscale techniques were taught successfully to the final year organic chemistry students

• Materials used to be 5g to 7g were reduced to less than 250mg

• Ever since many teachers have performed these microscale experiments and majority of students opined that it is not very difficult even in the high schools

Consequences of the adoption of the new technique in Laboratory:

• The use of the chemicals and subsequently the expenses of running the practical classes were radically reduced. eg: 20 students used up to 5 litres of diethyl ether everyday- now 500ml is more than adequate

• Smaller amounts to handle- students perform the experiments with more care

• Skill in handling equipment are markedly improved

Consequences of the adoption of the new technique in Laboratory:

• Time required for completing the experiments are decreased

• Even though the reaction time is the same, the time in setting up the reaction assembly, measuring the reactants, work up of the reactions, filtration, purification and drying the products would now be reduced to few minutes only

• To gain confidence and to verify result they can repeat the experiments as many times as they wish

Apparatus in Microscale Chemistry

1. Open ended capillaries

Used for the determination of melting points, now can be used to determine the boiling point and some of the routinely performed reactions such as color or group tests.

2. Pasteur Pippettes

• The most important apparatus in microscale laboratory

• Purposes : transfer of solutions, filtration and layer separation

2. Pasteur Pippettes

3. Hickman Head

• Formally used for collecting the distillate in vertical distillation

3. Hickman Head

4. Beral Pipettes

• Dropper-like pipettes, unbreakable and very convenient for storing most chemicals particularly table reagents.

• Volume of drop that can be retrieved is just about 0.03 to 0.04 ml, thus making it possible to add very small quantities easily

Suggestion

• Microscale chemistry should be introduced into our school curriculum especially in science and chemistry subjects.

• Not only it can save a lot of cost, it will increase the student’s laboratory skills

• Will provide opportunity for all students to do experiments

THANK YOU