Rates of Reactions

Which best defines "reaction rate"?

• Concentration change per unit time
• How long a reaction takes
• Adding a catalyst
• Combining reactants with products

Tags

NGSS.HS-PS1-5

A substance that increases speed of chemical reaction without being being changed is called:

• Catalyst
• Acid
• Base
• pressure

Tags

NGSS.HS-PS1-5

Activation energy is required to start a chemical reaction. What is activation energy?

• The energy needed for a reaction to occur
• The minimum amount of energy needed for a reaction to potentially occur
• The energy added by a catalyst
• The energy possessed by the products

Increase in temperature of the reactants can do one of the following

• Slow collision frequency
• Allow less effective collision between the particles
• Cause particles to lose speed
• Increase collision between the particles thus increasing the rate.

Tags

NGSS.HS-PS1-5

Increasing the pressure of a reacting vessel only affects:

• Gaseous reactants
• Solid reactants
• Liquid reactants
• None of the above

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

Which of the following is NOT a reason that increasing temperature increases reaction rate?

• Particles move faster
• Particles collide more often
• Particles have more effective collisions; with Ea
• Particles are more likely to have the correct geometry

Tags

NGSS.HS-PS1-5

Using this graph, which reaction is most likely cooled?

• A
• B
• C
• All of the above

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Using the following reaction, which factor would be the best to measure over time?
HCl + NaOH --> NaCl + HOH

• pH
• Mass of the system
• Liquid volume
• Color

Tags

NGSS.HS-PS1-5

One of the signs of a chemical reaction taking place is:

• Bubbles are produced in the reacting vessel
• Reactants are not combining
• Products are not forming
• Colour is not changing