CHEMISTRY · Multi-part · AP · Chemistry · Chemical Reactions · Chemical Reactions
Problem
Three particulate snapshots (I, II, and III) of a gaseous mixture are provided.
• In snapshot I, linear molecules consisting of one black sphere bonded to two red spheres are present, together with diatomic molecules composed of two red spheres bonded together.
• In snapshot II, the total number of spheres is unchanged. Molecules present include linear species with one black sphere bonded to one red sphere and bent molecules consisting of three red spheres bonded together.
• Snapshot III is identical to snapshot I.
The mixture contained only oxygen and carbon prior to any manipulation. An electric spark was passed through the container between snapshots I and II, and the system was allowed to return to its initial temperature before snapshot III was taken.
Respond to the following.
(1) Identify each molecular species present in snapshots I and II by chemical formula.
(2) Write a balanced chemical equation that relates the species observed in snapshot I to those in snapshot II.
(3) Explain whether the transformation occurring between snapshots I and II is a physical change or a chemical change. Refer explicitly to the particulate evidence in your explanation.
(4) Account for the observation that snapshot III is identical to snapshot I even though a chemical change occurred between snapshots I and II.