Note: The length of this experiment can be varied from 2 to 3 hours depending on the number of cooling curve trials on each sample. Lauric acid is suggested for use here for several reasons: it has a low tendency to supercool, it is not too expensive, and its melting point (around 43°C) means that 0 to 50°C thermometers can be used. If digital thermometers are available, myristic, palmitic and stearic acids are alternative choices and all four acids have the same freezing point depression constant. A computer interfaced temperature probe considerably facilitates this experiment. 1. List criteria that you think were used to select lauric acid as the solvent for this experiment. (At least 2) 2. Lange's Handbook of Chemistry lists k+ values (°C/m) for acetic acid (3.9) Propose 2 reasons that acetic acid was eliminated from consideration for this experiment. 3. Lange's Handbook of Chemistry lists kr values for benzene as 5.12 °C/m. Propose 2 reasons that benzene was not used in this experiment. 4. Lange's Handbook of Chemistry lists kr values for camphor as 37.7 °C/m. Propose 2 reasons that camphor was not used in this experiment. 5. Lange's Handbook of Chemistry lists kr values for strontium chloride as 107 °C/m. Propose 2 reasons that strontium chloride was not used in this experiment. 6. Lange's Handbook of Chemistry lists kf values for water as 1.86 °C/m. Propose 2 reasons that water was not used in this experiment. 7. There are other methods that you could use to find the molar mass of a substance (titration, quantitative precipitation, etc.). When would it be suitable or appropriate for 8. How do you account for the trend of melting points in the series of acids below? Acid Formula Melting point (°C) octanoic or (caprylic) CsH1602 17.5 decanolic (capric C10H2002 31.5 dodecanoic (lauric) C12H24O2 44.0 tetradecanoic (myristic) C14H28O2 55.0 hexadecanoic (palmitic) C16H3202 63.0 octadecanoic (stearic) CisH36O2 eicosanoic (arachidic 71.0 CaoH4002 77.0

Note: The length of this experiment can be varied from 2 to 3 hours depending on the number of cooling curve trials on each sample. Lauric acid is suggested for use here for several reasons: it has a low tendency to supercool, it is not too expensive, and its melting point (around 43°C) means that 0 to 50°C thermometers can be used. If digital thermometers are available, myristic, palmitic and stearic acids are alternative choices and all four acids have the same freezing point depression constant. A computer interfaced temperature probe considerably facilitates this experiment. 1. List criteria that you think were used to select lauric acid as the solvent for this experiment. (At least 2) 2. Lange's Handbook of Chemistry lists k+ values (°C/m) for acetic acid (3.9) Propose 2 reasons that acetic acid was eliminated from consideration for this experiment. 3. Lange's Handbook of Chemistry lists kr values for benzene as 5.12 °C/m. Propose 2 reasons that benzene was not used in this experiment. 4. Lange's Handbook of Chemistry lists kr values for camphor as 37.7 °C/m. Propose 2 reasons that camphor was not used in this experiment. 5. Lange's Handbook of Chemistry lists kr values for strontium chloride as 107 °C/m. Propose 2 reasons that strontium chloride was not used in this experiment. 6. Lange's Handbook of Chemistry lists kf values for water as 1.86 °C/m. Propose 2 reasons that water was not used in this experiment. 7. There are other methods that you could use to find the molar mass of a substance (titration, quantitative precipitation, etc.). When would it be suitable or appropriate for 8. How do you account for the trend of melting points in the series of acids below? Acid Formula Melting point (°C) octanoic or (caprylic) CsH1602 17.5 decanolic (capric C10H2002 31.5 dodecanoic (lauric) C12H24O2 44.0 tetradecanoic (myristic) C14H28O2 55.0 hexadecanoic (palmitic) C16H3202 63.0 octadecanoic (stearic) CisH36O2 eicosanoic (arachidic 71.0 CaoH4002 77.0

Chemistry & Chemical Reactivity

10th Edition

ISBN:9781337399074

Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Publisher:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Chapter11: Intermolecular Forces And Liquids

Section11.6: Properties Of Liquids

Problem 1.2ACP

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