Reaction Rates and Equilibrium Review

Chemical equilibrium is reached when the ________ are equal.

• concentrations of reactants and products

• potential energies of reactants and products

• rates of forward and reverse reactions

• change in energies of forward and reverse reactions

Tags

NGSS.HS-PS1-6

At chemical equilibrium, ____________ stops.

• variation of the concentration of reactants and products

• only forward reaction

• only reverse reaction

• both forward and reverse reactions

Which is the reactant - and why?

• as concentration decreases

• as concentration decreases

• as concentration increases

• as concentration increases

Tags

NGSS.HS-PS1-5

When the system X + 2 Y <=> Z has reached equilibrium, which of the following is TRUE?

• Forward reaction and Backward reaction stop.

• Forward reaction has sped up and backward reaction has slowed down.

• Forward and backward reactions occur at the same rate.

• Forward reaction has slowed down and backward reaction has sped up.

Crushing a solid catalyst into finer particles before adding it to a reaction mixture will:

• Decrease the reaction rate.

• Have no effect on the reaction rate.

• Increase the reaction rate.

• Stop the reaction.

Answer explanation

Increasing the surface area of a solid reactant will increase the reaction rate by providing more area for collisions between reactant particles.

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

• It is the energy released during the reaction

• It is the minimum energy required for reactants to transform into products

• It determines the color of the reaction mixture

• It is the energy required to break bonds in the products

In the process of baking bread, a catalyst affects the reaction by:

• Increasing the temperature of the oven.

• Decreasing the activation energy needed for the dough to rise.

• Increasing the concentration of yeast in the dough.

• Changing the equilibrium constant of the reaction.

Answer explanation

A catalyst affects a chemical reaction by decreasing the activation energy, making it easier for the reaction to occur.

Tags

NGSS.HS-PS1-5

For the reaction...
SO₂ + O₂ <=>  SO₃
If the equilibrium position shifts to the right, the concentration of ₂ will ___________.

• increase

• decrease

• remain the same

• double

Tags

NGSS.HS-PS1-6

What is the purpose of a catalyst on an equilibrium reaction?

• to increase the rate of forward reaction

• to increase rate of backward reaction

• in increase both forward and backward reaction rates

• no effect

0.600 moles of NO and 0.750 moles of O₂ are placed in an empty 2.00 L flask. The system is allowed to establish equilibrium. At equilibrium, there is [NO₂] = 4.1x10^-4. What will be the equilibrium concentrations of NO & O₂ in the flask?

• [NO] = 0.300, [O₂] = 0.375

• [NO] = 0.600, [O₂] = 0.750

• [NO] = 0.300, [O₂] = 0.375

Tags

NGSS.HS-PS1-7