Question

model 3 - boiling points of alcohols

alcohol\tformula\tnumber of carbons\tvolume of alcohol (ml)\tboiling point (°c)\troom pressure (kpa)
methanol\tch₃oh\t1\t75\t64.7\t101
ethanol\tch₃ch₂oh\t2\t75\t78.4\t101
propanol\tch₃ch₂ch₂oh\t3\t75\t97.1\t101
butanol\tch₃ch₂ch₂ch₂oh\t4\t75\t117.7\t101
pentanol\tch₃ch₂ch₂ch₂ch₂oh\t5\t75\t137.9\t101

1. describe the similarities and differences in the five alcohols used in the model 3 experiment.

each alcohol has more carbon then the last.

1. consider the experiment that produced the data in model 3.

a. what variable was purposefully changed in the experiment?
b. what variable changed as a result of changing the variable listed in part a?

1. what variable(s) in the model 3 data table remained constant among all the trials?

Explanation:

a. The number of carbon atoms in the alcohol molecules was purposefully changed. Different alcohols with increasing number of carbon - atoms were used.
b. The boiling point of the alcohol changed as a result. As the number of carbon atoms increased, the boiling point generally increased.
c. The volume of alcohol (75 mL) and room pressure (101 kPa) remained constant among all the trials.

Answer:

a. The number of carbon atoms in the alcohol molecules.
b. The boiling point of the alcohol.
c. The volume of alcohol and room pressure.