Chapter 4B + 5A

Which of the following changes will definitely lead to a faster reaction rate?

• lower temperature, addition of a catalyst and higher concentrations

• higher temperature, lower concentrations and the addition of a catalyst

• greater surface area, higher temperatures and higher concentrations

• greater surface area, lower temperatures and lower concentrations

In a closed equilibrium system…

• some products are produced and cannot escape. 

• all products are produced and can escape.

• all products are produced and cannot escape.

• some products are produced and can escape.

The temperature of a sample of helium gas is increased from 50℃ to 100℃. As a result of this change

• all gas particles will move faster but by different amounts.

• the speed of all gas particles will be doubled.

• the kinetic energy of all particles will be greater.

• the speed of many of the particles will be greater but not all.

If a chemical reaction has a theoretical yield of 25 grams and an actual yield of 7.5 grams, what is the percentage yield?

• 20%

• 30%

• 40%

• 50%

Which of the following statements is true regarding dynamic equilibrium?

• I only

• I and II only

• II and III only.

• I, II, and III.

When a catalyst is added to a reaction....

• an alternative reaction pathway is provided that requires a lower activation energy.

• the activation energy is increased enabling more particles to react.

• the kinetic energy of particles is increased, allowing more to collide successfully.

• the activation energy is unchanged but a higher percentage of particles are above that level.

In the decomposition of NOCl, the reaction is shown in the image below. In an equilibrium mixture at 30℃, the amount of

• Cl₂ is half the amount of NOCl

• NO will equal the amount of NOCl

• NO is far less than the amount of NOCl

• NO added to the amount of Cl₂ will give the amount of NOCl.

What is the correct equlibrium constant?

The concentrations in a mixture of the above gases at 100℃, are [SO₂] = 0.4 M, [O₂] = 0.4 M and [SO₃] = 0.4 M

Determine the new K and the statement that aligns with this value.

• The forward reaction needs to occur more than the back reaction to reach equilibrium.

• This reaction mixture is at equilibrium.

• The back reaction needs to occur more than the forward reaction to reach equilibrium.

• The back reaction will stop until equilibrium is reached.

4.8 mole of SO₂ and 3.0 mole of O₂ is introduced to an empty reactor. When equilibrium is reached

• 4.8 mole of SO₃  will have formed.

• 6.0 mole of SO₃  will have formed.

• SO₃ will not be present as it is the scarce reagent.

• The amount of SO₃ formed will equal the amount of SO₂ reacted