A laboratory investigation compares three different pure substances—A, B
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A laboratory investigation compares three different pure substances—A, B, and C—each observed at 20 °C. Students are provided only the numerical data below.
Average intermolecular separation (nm) Mean free path (nm)
Substance A 0.30 0.35
Substance B 0.32 25.0
Substance C 5.0 250
(The molecular diameter for all three substances is approximately 0.30 nm.)
(1) For each substance, determine the most probable phase at 20 °C based on the numerical data provided.
(2) Select one substance whose identification might reasonably be challenged. Construct a quantitative argument, using the data, that defends your phase assignment against an alternative classification.
(3) Describe one additional experimental measurement (other than temperature) that could be collected to strengthen confidence in the phase determinations, and explain what values you would expect for each phase.