Grade 11: Rate and progress of reactions-W9

What is rate?

• The measure of how much something changes within a specific time

• The velocity of light in vacuum.

• Speed of light.

• The measure of the volume of products.

In Chemistry, the rate of reaction is:

• time over concentration.

• change of the amount of reactant or product per time.

• concentration over volume.

• change of the amount of reactant only.

In (a), the energy is:

• Exothermic.

• Athermic.

• Endothermic.

In (b), the enthalpy change  $\Delta$  H is

• Negative.

• Postivie.

An endothermic reaction absorbs heat, and an exothermic reaction releases heat.

• True.

• False.

In (A), no reaction occurs, we say, it is:

• Ineffective collision.

• Effective collision.

Unstable arrangement of atoms that forms for a moment at the peak of the activation energy barrier is:

• Inactivated complex.

• Collision theory.

• Activated complex.

• Barrier.

For a chemical reaction to occur and have an effective collision:

• Particles must collide.

• Particles must collide at proper orientation.

• Particles must have enough kinetic energy to cross the activation energy barrier.

• All of the above.

Which factor best describes this image?

• Effect of particle size on reaction rate.

• Effect on concentration on reaction rate.

• Effect of temperature on reaction rate.

• Effect of catalyst on reaction rate.

What does MnO₂ represent in the tube (b)?

• An inhibitor.

• A product.

• A catalyst.

• An enzyme.