Use the following information and data to answer the next a through c questions. A student is performing a paper chromatography experiment. He spots two sample compounds (compound A and compound B) on the origin line at the bottom of his paper. He then places the paper into a beaker with a centimeter or so of liquid solvent and allows it to develop until the solvent front is near the top of the paper. Compound A eluted 8.23 cm up the paper. Compound B eluted 4.77 cm up the paper. The solvent front (distance solvent eluted) was measured at 10.46 cm from the origin. Part a) In the above experiment what component of the system is referred to as the stationary phase? a) the solvent b) the samples c) the paper d) none of the above Part b) Why is a pencil and not a pen used to draw the origin line upon which the samples are placed during the experiment? a) Pencil marks are more visible after the chromatogram has dried. b) Ink will react with the metal ions in the samples. c) Pencil marks won’t react with ammonia and calcium sulfide while ink will. d) Ink will separate into its components and move up the chromatogram paper. Part c) The calculated retention factors (Rfs) for sample A and B respectively are: a) 1.27 and 2.19 b) 0.456 and 0.787 c) 2.19 and 1.27 d) 0.787 and 0.456
Use the following information and data to answer the next a through c questions.
A student is performing a paper chromatography experiment. He spots two sample compounds (compound A and compound B) on the origin line at the bottom of his paper. He then places the paper into a beaker with a centimeter or so of liquid solvent and allows it to develop until the solvent front is near the top of the paper. Compound A eluted 8.23 cm up the paper. Compound B eluted 4.77 cm up the paper. The solvent front (distance solvent eluted) was measured at 10.46 cm from the origin.
Part a) In the above experiment what component of the system is referred to as the stationary phase?
a) the solvent
b) the samples
c) the paper
d) none of the above
Part b) Why is a pencil and not a pen used to draw the origin line upon which the samples are placed during the experiment?
a) Pencil marks are more visible after the chromatogram has dried.
b) Ink will react with the metal ions in the samples.
c) Pencil marks won’t react with ammonia and calcium sulfide while ink will.
d) Ink will separate into its components and move up the chromatogram paper.
Part c) The calculated retention factors (Rfs) for sample A and B respectively are:
a) 1.27 and 2.19
b) 0.456 and 0.787
c) 2.19 and 1.27
d) 0.787 and 0.456
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