Chemical Kinetics

Substance that speeds up chemical reactions but are not permanently changing themselves are called

• mechanisms.

• catalysts.

• inhibitors.

• activators.

The heat of reaction for an endothermic reaction will always be

• zero.

• greater than zero.

• less than zero.

• unpredictable.

The increase in reaction rate that accompanies increases in concentration is attributed to

• an increased frequency of collisions.

• lowered energies needed for collisions to be effective.

• increases in the effectiveness of collisions that occur.

• a reduction in the attractive fores between particles.

A change in the pressure exerted by reaction gases occurs when the volume is decreased or when

• the molecules collide more frequently with each other.

• the number of particles of gas is increased.

• both answer choices occur

• neither answer choices occur

The pulverizing of a solid substances to increase reaction rate effective because pulverizing

• increases the temperature.

• increases the surface area.

• reduces the bonding forces between molecules.

• changes the chemical make-up of the reacting substances.

The major difficulty in determining the steps in an overall reaction is the

• lack of knowledge about the final products.

• lack of any theoretical model to explain reactions.

• short-lived intermediate products.

• long period of time required for most reactions.

The difference in potential energy of the reactants and the products of a chemical reaction is the

• activation energy.

• heat released or absorbed.

• energy supplied by the catalyst.

• energy absorbed by the activated complex.

The energy required to physically break bonds among reactants and the products of a chemical reaction is the

• potential

• kinetic

• chemical

• electrical

Activation energy is the energy required to form the

• original bonds.

• activated complex.

• reaction complex.

• reactant molecules.

A catalyst increases the rate of chemical reaction by

• causing more collisions between molecules.

• increasing the energy of the particles in the reaction.

• lowering the activation energy of the reaction.

• raising the activation energy so that the colliding molecules have more energy.

Tags

NGSS.HS-PS1-5