Review - Reaction Rates

What criteria must be met for reactant collisions to result in a successful product?

• The reactants must collide with each other

• The reactants must collide with enough energy and be in the right positions

• The reactants must have enough energy to form the activated complex

Collisions may take place between: 

• Atoms
• Ions
• Molecules
• All of the above

Tags

NGSS.HS-PS2-3

NGSS.HS-PS3-5

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

• Slow collision frequency
• Allow less effective collision between the particles
• Neutralise the reaction
• increase collision between the particles thus increasing the rate.

Tags

NGSS.HS-PS1-5

Which of the following increase the reaction rate?

• less surface area
• lower temperature
• an inhibitor
• increased concentration

Tags

NGSS.HS-PS1-5

Why does a higher temperature increase the rate of a reaction?

• it increases both the frequency and energy of particle collisions
• it only increases the frequency of particle collisions
• it only increases the energy of particle collisions
• it reduces the activation energy of the reaction

Tags

NGSS.HS-PS1-5

Which has more surface area?

• Large chunks of chalk

• Cube of sugar

• Powdered sugar

• Small chunks of sugar

Which 2 trials show the effect of a catalyst on reaction rate, and what is the effect of adding a catalyst?

• 1 and 5; rate increases when a catalyst is added

• 2 and 5; rate decreases when a catalyst is added

• 3 and 5; rate increases when a catalyst is added

• 4 and 5; rate decreases when a catalyst is added

Tags

NGSS.HS-PS1-5

Which 2 trials show the effect of increasing [HgCl₂] on reaction rate, and what is the effect of increasing [HgCl₂]?

• 1 and 3; rate stays the same when [HgCl₂] increases; thus HgCl₂ is a zero order reactant

• 2 and 3; rate increases (quadruples) when [HgCl₂] increases (doubles); thus HgCl₂ is a second order reactant

• 3 and 4; rate increases when [HgCl₂] increases and is somewhere between second and third order

• 4 and 6; rate increases when [HgCl₂] increases and is somewhere between first and second order

Tags

NGSS.HS-PS1-5

What effect does chopping vegetables have on their cooking time and why? (using principles of collision theory)

• Chopped vegetables are at a higher temperature and therefore take less time to cook

• Chopped vegetables have catalysts and therefore take less time to cook

• Chopped vegetables have increased surface area and therefore take less time to cook

• Chopped vegetables are more concentrated and therefore take more time to cook

Tags

NGSS.HS-PS1-5

What factors affect reaction rate?

• size of atoms

• temperature

• concentration

• surface area

• catalysts

Tags

NGSS.HS-PS1-5