chem12 final review

The rate of a reaction can be determined by measuring which of the following over time?

• Temperature
• Reactant concentration
• Color change
• Pressure

In a reaction energy diagram, what does the peak represent?

• Products
• Reactants
• Activation energy
• Intermediate

Which of the following processes is exothermic?

• Melting ice
• Boiling water
• Condensation of steam
• Sublimation of dry ice

Which statement is true for an endothermic reaction?

• Absorbs heat from surroundings
• Releases heat to surroundings
• Does not involve heat exchange
• Is always spontaneous

Which step in a multi-step reaction mechanism is the rate-determining step?

• The fastest step
• The step with the highest activation energy
• The step with the lowest activation energy
• The final step

What is the enthalpy change (ΔH) for an exothermic reaction?

• Positive
• Negative
• Zero
• Cannot be determined

According to the collision theory, which factor does not affect the rate of reaction?

• Concentration of reactants
• Temperature
• Orientation of molecules
• Particle size

Which of the following correctly describes the kinetic energy of molecules at higher temperatures?

• It decreases
• It remains the same
• It increases
• It becomes zero

What is the role of activation energy in a chemical reaction?

• To decrease reaction rate
• To break reactant bonds
• To increase product stability
• To decrease reaction equilibrium

In a reaction mechanism, what is an intermediate?

• A catalyst
• A product
• A reactant
• A species formed and consumed in steps