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Assessment: Chemical Kinetics: Rates of Reaction

Answer every question, then submit to see your score and which topics to review.

Part A — Concept Questions

Why do most collisions between reactant particles NOT result in a reaction?

Easy

Is activation energy ever negative for a reaction?

Medium

Part B — Formula & Application

A reactant's concentration drops from 1.20 mol/L to 0.90 mol/L over 25 seconds. Find the average rate (mol/(L·s)).

Medium
mol/(L·s)

A reaction has a rate of 0.008 mol/(L·s) at 15°C. Using the "rate doubles every 10°C" rule, estimate the rate (mol/(L·s)) at 35°C.

Medium
mol/(L·s)

Part C — Problem Solving

A catalyst lowers a reaction's activation energy. On a Maxwell–Boltzmann distribution graph (at the same temperature), what changes?

Hard

Two identical masses of calcium carbonate react with excess acid — one as a single large lump, one crushed into a fine powder. Which statement is correct?

Hard

Part D — Real-Life Application

Why does food stored in a refrigerator stay fresh much longer than food left at room temperature?

Medium

Part E — Challenge

A catalyst is added to a reaction. Which of the following does the catalyst change?

Hard

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