Evaporation and Distillation Laboratory Worksheet Student Name______

Aim: To separate mixtures using evaporation and distillation. ​

Introduction: Evaporation is the process by which water changes from a liquid to a gas or ​ ​ ​ vapor. It can be used to obtain dissolved solids (solutes) present in water.

Distillation is a process of separating the components of a liquid mixture by evaporation and condensation. It is used to separate a mixture of liquids on the basis of different boiling point.

Materials Required For evaporation ­ 250ml pyrex beaker ­ Bunsen burner, wire gauze and tripod stand. ­ Concentrated salt and water solution ­ Porcelain chips ­ 10 ml measuring cylinder ­ Thermometer ­ Digital scale Materials Required For Distillation ­ Retort stand with clamp ­ Bunsen burner, wire gauze and tripod stand. ­ 10 ml measuring cylinder ­ Thermometer ­ Round bottom flask ­ Porcelain chips ­ Liebig condenser ­ Parrafin wax ­ 2 by 60 cm 5 mm diameter flexible hose ­ Water and ethanol mixture.

Risks ­ Burning and scalding risks is quite significant as this investigation involves flame source and hot liquids.

Safety ­ Always wear goggles and hand gloves ­ Never come close to open flame ­ Keep combustibles such as loose clothing and papers away from bunsen flame ­ Never look into a beaker or flask of boiling or hot liquid ­ Move slowly and carefully in the laboratory ­ Do not attempt to touch any part with bare hands Procedure for evaporation

­ Pour 50 ml of salt and water solution into the evaporating basin ­ Light up the bunsen flame on medium flame ­ Place the beaker of salt solution on a gauze mat and tripod stand and place it directly over the bunsen flame. ­ Continue heating until all the water has turned to steam and only salt is left behind (this will take time so you guys can also start up the distillation experiment during this time) ­ Ensure that you keep an eye on evaporation set up and record your observation and results below

Observation and results

1. At what temperature did water start to evaporate ( was it 100 ℃ or less ) ?

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2. How long did it take to evaporate all 50 ml of water?

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3. Was the salt obtained lumpy or in crystal form like the normal salt?

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4. What other mixtures do you think can be separated using this method? ______

Conclusion ______

Procedure for Distillation

­ Ensure that the distillation apparatus is set up as shown in the diagram above. ­ Place about 2­3 porcelain chips into the flask ­ Place 50 ml of ethanol and water mixture in the flask by using a measuring cylinder. ­ While heating ensure that the temperature does not go beyond 80 ℃ otherwise water will also start evaporating and distillate will be containing both ethanol and water. ­ Stop heating once about 25 ml of distillate is collected. ­ Once cooled test the distillate and residue by smelling them and bit rubbing a bit on your palm.

Observation and results 1. Were you able to actually see the ethanol evaporating and condensing?

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2. At what temperature did ethanol start to evaporate? How does this compare to the boiling point of ethanol which is 78.8 ℃ ?

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3. Compare and contrast the processes of evaporation and condensation

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4. If you are stranded on a small island devoid of freshwater discuss how would you be able to obtain drinking water using a distillation apparatus.

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Conclusion

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