ExptFP - Expt FP 1 Freezing Point Depression(FP Objective...

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Expt FP 1 Freezing Point Depression (FP) Objective The purpose of this experiment is to use the freezing point depression of the solute camphor (C 10 H 16 O) - 1,7,7-Trimethylbicyclo[2.2.1]heptan-2-one in the solvent 1-octadecanol (C 18 H 37 OH) to determine the molecular weight of camphor. Temperature data will be obtained using a Logger Pro interface and an iMac computer. Caution Keep all chemicals away from the electronic devices. Place the three test tubes you used back where you found them. These tubes are reused each week. It is very important to not contaminant the tubes. Always make sure temperature probe is clean before placing into test tube. When probe is removed from hot liquid in test tube, any substance sticking on the probe should be immediately wiped off. Background Theory First read the website below for introduction to Colligative Properties and FP depression. http://dbhs.wvusd.k12.ca.us/webdocs/Solutions/BP-Elev-and-FP-Lower.html ChemTeam: Boiling Point Elevation and Freezing Point Depression Next, for thermodynamic derivation details read this website http://antoine.frostburg.edu/chem/senese/101/solutions/faq/thermo-explanation-of-freezingpoint- depression.shtml General Chemistry Online: FAQ: Solutions: How can freezing point. .. We use the last equation they presented in the second website to derive the equations that you will use in this work. They wrote (notation simplified below and sign error corrected) T = ( R T 0 2 / H f ) X A (1) where T is the freezing point depression written as a positive value T = To – T f , R is the gas constant, T 0 is the melting point of the pure liquid, T f is the melting point of the solute-solvent
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Expt FP 2 mixture which will always be lower than the pure solvent, H f is the molar heat of fusion for the liquid solvent, and X A is the mole fraction of solute. Since the mole fraction of solute A dissolved in solvent B is defined as the moles of solute A over the total moles of the mixture we can write X A = mol A / ( mol A + mol B ) (2) In a dilute mixture of A where there is much more solvent than solute, mol B ~ (mol A + mol B ) and the previous equation can be approximated by X A = mol A / ( mol B ) (3) The moles of the solute A can be written as mol A = w/M (4) where w is the weight or mass (grams) of the solute and M is the molar mass (g/mol) of
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ExptFP - Expt FP 1 Freezing Point Depression(FP Objective...

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