AP Chemistry:: Kinetics

What is CHEMICAL KINETICS, as a general area of study within chemistry?

- **A)** The study of the RATES at which chemical reactions occur, and the specific FACTORS that influence how quickly or slowly a reaction proceeds
- **B)** Kinetics is concerned exclusively with a reaction's FINAL EQUILIBRIUM position, rather than the rate at which it reaches that position
- **C)** This area of study has no actual relationship to the speed at which chemical reactions occur
- **D)** Chemical kinetics refers only to whether a reaction is EXOTHERMIC or ENDOTHERMIC, with no relationship to how fast the reaction occurs

What is REACTION RATE, and how is it typically defined quantitatively in terms of reactant or product CONCENTRATION?

- **A)** Reaction rate refers only to the TOTAL AMOUNT of product eventually formed, with no relationship to how quickly that amount is reached
- **B)** This concept has no actual relationship to how concentration changes over time during a reaction
- **C)** The CHANGE in concentration of a reactant (decreasing) or product (increasing) PER UNIT TIME -- essentially, how quickly reactants are consumed or products are formed
- **D)** Reaction rate is always measured as a FIXED, CONSTANT value that never changes throughout the entire course of a reaction

According to COLLISION THEORY, what TWO conditions must generally be met for a collision between reactant particles to result in a SUCCESSFUL reaction (rather than just an ineffective bounce)?

- **A)** A successful reaction requires particles to collide with LESS than the minimum activation energy, rather than sufficient energy to overcome it
- **B)** Collision theory requires only that particles collide with ANY amount of energy, with orientation playing no actual role in determining a successful reaction
- **C)** The colliding particles must have SUFFICIENT ENERGY (enough to overcome the activation energy barrier) AND the correct ORIENTATION (proper geometric alignment) at the moment of collision
- **D)** This theory has no actual relationship to the energy or orientation of colliding particles affecting reaction success

What is ACTIVATION ENERGY (Ea), as a key concept in collision theory and reaction kinetics?

- **A)** The MINIMUM amount of energy that colliding reactant particles must possess in order to successfully react and form products -- essentially, an 'energy barrier' that must be overcome
- **B)** Activation energy is always ZERO for every chemical reaction, meaning no minimum energy threshold ever exists
- **C)** This concept has no actual relationship to a minimum energy threshold required for a successful reaction to occur
- **D)** Activation energy refers to the TOTAL energy released by a reaction overall, rather than a minimum energy threshold required to initiate the reaction

How does INCREASING the CONCENTRATION of a reactant generally affect the RATE of a reaction, and WHY (based on collision theory)?

- **A)** Reactant concentration has no actual relationship to how frequently reactant particles collide with each other
- **B)** Increasing reactant concentration always DECREASES reaction rate, the reverse of the actual general relationship predicted by collision theory
- **C)** Reaction rate is completely UNAFFECTED by changes in reactant concentration, remaining exactly constant regardless of concentration changes
- **D)** Increasing reactant concentration generally INCREASES reaction rate, because a HIGHER concentration means MORE reactant particles are present in a given volume, leading to MORE FREQUENT collisions between them

How does INCREASING TEMPERATURE generally affect the RATE of a reaction, and WHAT TWO specific reasons (based on collision theory) explain this effect?

- **A)** Temperature has no actual relationship to particle speed, collision frequency, or the proportion of successful collisions in a reaction
- **B)** Increasing temperature always DECREASES reaction rate, the reverse of the actual general relationship predicted by collision theory
- **C)** Higher temperature only affects collision FREQUENCY, with no actual effect on the proportion of collisions having sufficient activation energy
- **D)** Increasing temperature generally INCREASES reaction rate, because higher temperature causes particles to move FASTER, resulting in BOTH more FREQUENT collisions AND a GREATER PROPORTION of those collisions having enough energy to exceed the activation energy barrier

How does INCREASING the SURFACE AREA of a solid reactant (e.g., by grinding it into smaller pieces) generally affect the RATE of a reaction involving that solid, and WHY?

- **A)** Surface area has no actual relationship to how much of a solid reactant is exposed and available for collision with other reactants
- **B)** Increasing surface area always DECREASES reaction rate, the reverse of the actual general relationship
- **C)** Increasing a solid reactant's surface area generally INCREASES reaction rate, because MORE of the solid's particles are EXPOSED and available to collide with other reactants at any given moment
- **D)** Reaction rate involving a solid reactant is completely UNAFFECTED by changes in the solid's surface area or particle size

What is a CATALYST, and how does a catalyst generally increase REACTION RATE without being permanently consumed by the reaction?

- **A)** A substance that INCREASES reaction rate by providing an ALTERNATIVE reaction pathway with a LOWER activation energy -- the catalyst PARTICIPATES in the reaction mechanism but is REGENERATED (not permanently consumed) by the end of the reaction
- **B)** This concept has no actual relationship to lowering a reaction's activation energy or providing an alternative reaction pathway
- **C)** A catalyst always INCREASES a reaction's activation energy, the reverse of the actual mechanism by which catalysts speed up reactions
- **D)** Catalysts are always permanently CONSUMED by the reaction, becoming part of the final product mixture rather than being regenerated