Experimental Design and Separation Techniques

How close the result values are to the true value

How consistent (close to each other) the result values are

It will achieve similar results if repeated with the same method.

Variables kept constant on purpose

The property that we change, which affects the results

The property that is affected by the independent variable (the results)

A random error is unpredictable; for example, a human error A systematic error is a problem with the experiment.

A result that doesn’t follow the pattern at all

To separate a liquid from an insoluble solid

To separate two liquids

To separate a solid and a liquid (done if the liquid is required)

To separate two miscible liquids

To separate two (or more) liquids

To separate two immiscible liquids

To separate a liquid and solid

• Pour the mixture into a funnel with filter paper and a beaker below • Wait for the solution to pass through The solid solute will stay in the filter paper (residue) The solvent will pass through the filter paper and into the beaker (filtrate)

• Pour your solution into a beaker • Heat the solution on a hot plate until the solvent evaporates, leaving behind the solute

• Pour your solution into a distillation flask • Heat it and measure the temperature with a thermometer • Once the liquid solvent starts evaporating, pour cold water into the condenser, which will cool the vapor and turn it into a liquid, which will be collected in a conical flask

• Pour your solution into a distillation flask • Heat it and record the temperature at which the solvent starts evaporating with a thermometer • Once the liquid solvent starts evaporating, pour cold water into the condenser, which will cool the vapor and turn it into a liquid, which will be collected in a conical flask (Used if the boiling points of the components are close.)

• Fill up a beaker to ~2cm with a solvent. • Place the solute at 2.5cm on chromotography paper. • Wait until the solvent reaches near the top of the paper • Dry the chromotography paper with a hot plate or hairdryer • Record where the different components of the solute are on the paper and calculate the Rf value.

• Pour a mixture into a separating funnel with the stopcock on • Wait until the lower density liquid floats on top • Open the stopcock and wait for the higher density liquid to drip into the beaker below. • Close the stopcock

• Put the solvent and more solute than needed in a beaker and stir with a glass rod • Filter the mixture to remove excess solvent (use filter paper and a funnel) • Take the filtrate and evaporate with a bunsen burner, tripod, and gauze until crystals start to form. The solution will be in an evaporating basin on top of a beaker with boiling water • Leave the evaporating basin overnight to evaporate the rest of the water.

residue

filtrate