CH 4 Chemical Reactions and Systems Quiz

What does the temperature of a substance represent?

• The average potential energy of the particles

• The average kinetic energy of the particles

• The total energy of the particles

• The chemical energy of the particles

What is the effect of increased kinetic energy on reactant collisions?

• Collisions occur less frequently.

• Collisions occur more frequently.

• Collisions stop occurring.

• Collisions become weaker.

What is the effect of increasing the concentration of a reactant in a solution?

• It decreases the collision frequency.

• It increases the collision frequency.

• It has no effect on the collision frequency.

• It stops the reaction.

What is a common misconception in collision theory?

• All collisions result in a reaction

• Frequency and proportion are the same

• Temperature does not affect reaction rate

• Pressure has no impact on reaction rate

How can the speed of a reaction be measured?

• By observing changes in color only

• By observing changes in temperature, pH, mass, or color

• By measuring the volume of liquid

• By counting the number of particles

What is observed when using a balance to measure reaction rates?

• Change in color

• Change in temperature

• Change in mass

• Change in volume

Which of the following statements about rates and the collision theory model is true?

• Endothermic reactions are always slower than exothermic reactions.

• All particles have the same kinetic energy at a fixed temperature.

• Reactant particles need to collide with sufficient energy to react.

• The rate of a reaction at a constant temperature increases as the reaction proceeds.

Which concentration of HCl showed the slowest bubbling?

• 0.5 M

• 1.0 M

• 1.5 M

• 2.0 M

Why do nails on the sun-exposed side of a boat rust faster than those on the shaded side?

• Higher temperature increases reaction rate

• Sunlight prevents rusting

• Shaded side is wetter

• Sunlight decreases reaction rate

What is a catalyst?

• A substance that increases the temperature of a reaction

• A substance that provides an alternate reaction pathway with lower activation energy

• A substance that decreases the concentration of reactants

• A substance that changes the color of a reaction