Reaction Kinetics

Limestone chunks are reaction with hydrochloric acid solution at constant temperature with average speed. If we crash the chunks of limestone into powder how would speed of reaction change?

• Reaction speeds up

• Reaction does not change

• Reaction slows down

• Reaction stops

Tags

NGSS.MS-PS1-2

Decreasing the particle size increases the reaction rate because

• It makes particles move faster

• It increases the likelihood of collisions with the correct geometry

• It decreases the surface area available to react

• It increases the number of collisions

The catalyst alters the rate of a chemical reaction by,

• providing an alternative pathway with a lower Ea

• changing the products formed in the direction of the reaction

• providing a surface on which the molecules react

• increasing the frequencies of collisions between molecules

Tags

NGSS.HS-PS1-5

Which of the following are true of reaction rates?

• II+III+IV

• I+IV

• II + III

• I+II+III

Tags

NGSS.HS-PS1-5

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 a chemical reaction, if the concentration of reactants is increased, what happens to the reaction rate?

• It decreases

• It increases

• It remains unchanged

• It initially increases, then decreases

Tags

NGSS.HS-PS1-5

During a science fair, Abigail, Evelyn, and Priya conducted an experiment to observe the rate at which a sugar cube dissolves in water at room temperature. What is the unit of the reaction rate they observed?

• Molarity (M)

• Molarity per second (M/s)

• Kelvin (K)

• Joules (J)

Answer explanation

The unit of reaction rate in a chemical reaction is Molarity per second (M/s), which represents the change in concentration of reactants or products per unit time.

Tags

NGSS.HS-PS1-5

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-PS1-4

Which factors increase the rate of a reaction?

• increasing temperature

• increasing concentration

• increasing surface area

• all of the above

Tags

NGSS.HS-PS1-5