Difference between revisions of "GCSE Chemistry Required Practical: Calculating Retention Factors"
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#Suspend the [[chromatography]] paper in a suitable [[solvent]] just below the pencil line with most of the paper above the [[solvent]]. | #Suspend the [[chromatography]] paper in a suitable [[solvent]] just below the pencil line with most of the paper above the [[solvent]]. | ||
#Wait until the [[solvent]] stops rising up the paper. | #Wait until the [[solvent]] stops rising up the paper. | ||
| + | #Remove the paper from the [[solvent]] and allow it to dry. | ||
#Use a ruler to measure the distance that the [[solvent]] has traveled up the paper. | #Use a ruler to measure the distance that the [[solvent]] has traveled up the paper. | ||
#Use a ruler to measure the distance that the different [[dye]]s have traveled up the paper. | #Use a ruler to measure the distance that the different [[dye]]s have traveled up the paper. | ||
Revision as of 11:36, 29 January 2019
Key Stage 4
Meaning
Use a Chromatography experiment to produce a Chromatogram and calculate the Retention Factors (Rf) for they dyes found within different inks.
Method
- Take a piece of chromatography paper of width 6cm and height 10cm.
- Using a ruler draw a line with pencil across the width 2cm up from the end.
- Add a dot of each unknown sample on the pencil line at 1cm intervals.
- Suspend the chromatography paper in a suitable solvent just below the pencil line with most of the paper above the solvent.
- Wait until the solvent stops rising up the paper.
- Remove the paper from the solvent and allow it to dry.
- Use a ruler to measure the distance that the solvent has traveled up the paper.
- Use a ruler to measure the distance that the different dyes have traveled up the paper.
- Use the following equation to find the Retention Factor for each dye:
\[R_f = \frac{d_c}{d_s}\]
- Where:
- Rf = Retention Factor
- dc = distance moved by the chemical
- ds = distance moved by the solvent