Collision Theory, Kinetics: Collision Theory ALL VERSIONS 2025 | LATEST AND ACCURATE REAL EXAM QUESTIONS WITH DETAILED ANSWERS | VERIFIED FOR GUARANTEED PASS | LATEST UPDATE

Why don't all collisions between particles with the necessary activation energy lead to a reaction? A. The particles are too small B. They must collide in the right orientation C. The temperature is too high D. The pressure is too low Rationale: Even with enough energy, particles must also align correctly to break and form bonds. Which of the following is not a factor affecting the rate of a chemical reaction? A. Temperature B. Concentration C. Volume of the flask D. Catalyst Rationale: Volume isn't a direct factor; the other four (including pressure and surface area) affect collision frequency and energy. What is an endothermic reaction? A. One that releases heat B. One where energy is conserved C. A reaction where products have more energy than reactants D. A reaction that creates heat Rationale: Endothermic reactions absorb heat, so the products end with more energy. What is true about an exothermic reaction? A. Products have more energy than reactants B. Reactants and products have equal energy C. Products have less energy than reactants D. It only occurs in combustion reactions Rationale: Exothermic reactions release energy, resulting in lower energy products. Why don't more collisions necessarily increase the rate of reaction? A. The particles bounce away too fast B. Only collisions with enough energy and correct orientation lead to reactions C. Extra collisions use up the reactants D. More collisions reduce temperature Rationale: Only effective collisions—those with proper energy and orientation— result in reactions. What is a catalyst? A. A reactant used up in the reaction B. A product formed in a side reaction C. A substance that alters the rate of a reaction without being consumed D. A compound that increases the temperature Rationale: Catalysts provide an alternative pathway with lower activation energy and are not used up. How do catalysts increase the rate of a reaction? A. They increase the pressure B. They heat the system C. They provide an alternative path with lower activation energy D. They remove heat from the reaction Rationale: Lower activation energy means more particles can react upon collision. Which of the following best defines a successful collision? A. A collision with two gases only B. A low-energy collision C. A collision with enough energy and correct orientation D. A collision in cold temperatures Rationale: According to collision theory, both energy and orientation must be correct for a reaction. Which of the following increases the rate of reaction? A. Decreasing surface area B. Lowering temperature C. Decreasing pressure D. Increasing concentration Rationale: More concentration means more particles, increasing collision frequency. Why does increasing temperature increase reaction rate? A. Particles become larger B. Particles move faster and collide more energetically C. The activation energy decreases D. The volume of gas increases Rationale: Faster particles collide more often and with greater energy. Why does increasing pressure increase reaction rate in gases? A. It lowers the energy needed B. It makes particles smaller C. It forces particles closer, increasing collisions D. It decreases volume and heat Rationale: Higher pressure compresses gas molecules, raising collision frequency. What is the minimum energy needed for a reaction to occur? A. Kinetic energy B. Transition energy C. Potential energy D. Activation energy Rationale: Activation energy is the minimum threshold for bond breaking/forming. What are the 3 conditions for a successful collision according to Collision Theory? A. Must be under pressure, cold, and wet B. Particles must have color, charge, and mass C. Particles must collide, have correct orientation, and enough energy D. Atoms must be different, far apart, and vibrating Rationale: All three conditions are essential for a reaction to proceed. Which statement is true regarding concentration and collision rate? A. Lower concentration leads to more collisions B. Higher concentration increases collision frequency C. Concentration has no effect on reaction rate D. Collisions are unrelated to concentration Rationale: More particles in a given volume = more frequent collisions. What happens to the kinetic and potential energy of particles as they approach transition state? A. KE increases, PE remains constant B. KE decreases, PE increases C. Both KE and PE drop D. KE and PE are equal Rationale: As particles collide, KE converts into PE to stretch bonds toward reaction. What is the activated complex or transition state? A. A new product B. An unreacted atom C. A temporary, unstable intermediate between reactants and products D. A catalyst Rationale: The activated complex is formed momentarily as bonds break/form. What does the Arrhenius Equation describe? A. The pressure of gases B. The speed of light C. The temperature dependence of reaction rate D. The concentration of ions Rationale: The equation shows how temperature affects the rate constant k based on activation energy. Why doesn't a book of matches spontaneously ignite? A. Matches don’t contain reactants B. Activation energy hasn’t been met yet C. They're kept in cold places D. Reactions only happen in flames Rationale: The energy threshold for ignition (activation energy) has not been reached. Which of the following best describes the effect of increasing temperature on reaction rate? A. Decreases the rate B. Increases the number of particles C. Increases frequency and energy of collisions D. Slows down molecule motion Rationale: Higher temperatures cause more frequent and energetic collisions. Which term describes collisions that result in chemical reactions? A. Partial collisions B. Ineffective collisions C. Elastic collisions D. Effective collisions Rationale: Effective collisions are those with the right energy and alignment to cause a reaction. What do we call collisions that do not lead to a chemical reaction? A. Effective collisions B. Ineffective collisions C. Energetic collisions D. Productive collisions Rationale: Ineffective collisions lack either the energy or proper orientation needed. Which statement best describes Transition State Theory? A. It explains only exothermic reactions B. It describes how catalysts are formed C. It focuses on bond strength alone D. It explains energy changes during reactions and the formation of activated complexes Rationale: Transition State Theory explains how energy is used to stretch bonds to form an unstable intermediate—the activated complex—leading to a reaction. According to Transition State Theory, what happens when particles collide and the potential energy meets or exceeds the activation energy? A. A reversible reaction begins B. Bonds are broken and new ones are formed C. The reactants cool down D. The particles bounce away unchanged Rationale: When potential energy exceeds activation energy, the transition state forms and bonds can break/form. What is the 'activated complex' in a chemical reaction? A. The final product B. An intermediate molecule that's stable C. A temporary and unstable structure formed during a reaction D. The reactant with high energy Rationale: The activated complex is the unstable combination of atoms at the peak of the energy barrier. What is the role of the frequency factor (A) in the Arrhenius equation? A. Determines the type of catalyst B. Shows the total energy released C. Represents the rate of successful collisions D. Measures the color of the solution Rationale: The frequency factor reflects how often particles collide with correct orientation. Which of the following is not part of the Arrhenius equation? A. Activation energy B. Reaction enthalpy C. Temperature in Kelvin D. Frequency factor Rationale: Reaction enthalpy is not included in the Arrhenius equation; it focuses on kinetics, not thermodynamics. Which of the following correctly shows components of the Arrhenius equation? A. A, Ea, R, T B. C, D, M, K C. P, V, n, R D. H, S, G, T Rationale: The Arrhenius equation uses A (frequency factor), Ea (activation energy), R (gas constant), and T (temperature).