Objective: The purpose of this experiment was to identify compounds in a mixture by Rf values and to determine the best solvent to use. Also is the analysis of mixtures before, during and separation.
Possible solvents:
Hexane
MW- 86.17 g/mol
Hazards-flammable, harmful if swallowed
Melting pt / boiling pt (degree Celsius) - 69
Density-.6548 g/ml [pic]
Methanol
MW-32.04 g/mol
Hazards- flammable, eye irritant
Melting pt / boiling pt- 65
Density-.7918 g/ml
[pic]
Methylene chloride
[pic]
MW- 84.93 g/mol
Hazards- toxic if inhaled
Melting pt / boiling pt- 39.6
Density-1.33g/ml
Possible Components
Biphenyl
Methylene chloride
MW- 154.21 g/mol
Hazards- acute if high levels
Melting pt / boiling pt- 255
Density-1.118 g/ml
[pic]
Benzophenone
MW- 182.217 g/mol
Hazards- harmful if swallowed
Melting pt / boiling pt- 65/298
Density-1.311 g/ml
[pic]
Benzhydrol
MW- 184.24
Hazards-
Melting pt / boiling pt- 305.4
Density-1.08 g/ml
[pic]
Caluations
Ratio f = Distance compound traveled -------------------------------------- Distance the compound could have traveled
Hexane- (two separation circles)
(1). 1.7cm/4.8cm= .3541cm
(2). 0.4cm/4.8cm= .0833cm
Methylene Chloride (three separation circles)
(1). 2.2cm/5.2cm= 0.4230cm
(2). 3.1cm/5.2cm= 0.5961cm
(3). 4.0cm/5.2cm= 0.7692cm
Methanol (no seperation)
(1). 3.5cm/4.8cm= 0.7291cm
Biphenyl (no seperation)
(1). 3.9cm/5.2cm= 0.75cm
Benzophenone (no seperation)
(1). 3.1cm/5.2cm= 0.5961cm
Benzhydrol
(1). 2.3cm/5.2cm= 0.4423cm
Unknown B (two separation circles)
(1). 3.2cm/5.2cm=0.6153cm
(2). 2.4cm/5.2cm=0.4615cm
Results: Based on the Rf results Methylene chloride is a better solvent for this experiment than methanol and hexane. This is because silica gel is very polar and methylene chloride is slightly polar but it is mostly non-polar which allow the compound to