Topic 9 Kinetics 1 Flashcards Preview

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Flashcards in Topic 9 Kinetics 1 Deck (16)
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1
Q

What is chemical kinetics?

A

The study of the rate of chemical reactions.

2
Q

What is the rate of reaction?

A

The rate of which a product is formed or reactant is removed.

This can be measured by analysing a property of the mixture such as the volume, and observing how it changes over time.

3
Q

What is a catalyst?

A

A substance that increases the rate of reaction without altering the reaction that occurs.

Catalysts work by removing or lowering barriers preventing a reaction.

4
Q

What is the mechanism of a reaction?

A

A description of how a reaction occurs displaying the bonds which are broken and made.

5
Q

What is a phase?

A

A phase is one of the three states of matter. Solid, liquid or gas.

6
Q

What is a heterogenous catalyst?

A

A catalyst that is in a different phase from the reactants in the reaction.

7
Q

What is the Maxwell-Boltzmann Distribution?

A

A graph that displays the spread of molecular kinetic energies for a gas at a particular temperature.

It displays that there is a wide spread of molecular energies so the molecules are moving at different speeds.

8
Q

What is activation energy?

A

The minimum energy required for successful collisions between molecules to occur.

9
Q

What is a transition state?

A

The state of the reacting atoms, molecules or ions when they reach the required activation energy in a reaction.

Transition states occur for such a short period of time that they can not be detected or isolated.

10
Q

What is a reaction profile?

A

A graph which shows the total enthalpy of the atoms, molecules or ions changes during the progress of a reaction from reactants to products.

11
Q

What are intermediates?

A

Atoms, molecules and ions which do not appear in the balanced equation but which are formed during one step of a reaction, and then used up in the next step.

12
Q

How does temperature affect the rate of reaction?

A

Increased temp - Particles gain more kinetic energy, therefore resulting in more frequent successful collisions, resulting in a faster rate of reaction.

Decreased temp - Particles gain less kinetic energy, therefore resulting in less frequent successful collisions, resulting in a slower rate of reaction.

13
Q

How does pressure affect the rate of reaction?

A

Increased pressure - Particles are closer together, therefore resulting in more frequent successful collisions, resulting in a faster rate of reaction.

Decreased pressure - Particles are further apart, therefore resulting in less frequent successful collisions, resulting in a slower rate of reaction.

14
Q

How does surface area affect the rate of reaction?

A

Increased SA - A higher number of particles are able to react, therefore resulting in more frequent successful collisions, resulting a faster rate of reaction.

Decreased SA - A lower number of particles are able to react, therefore resulting in less frequent successful collisions, resulting a slower rate of reaction.

15
Q

How does a catalyst affect the rate of reaction?

A

With catalyst - The activation energy is lowered, so more particles have the required activation energy, therefore resulting in more frequent successful collisions, resulting in a faster rate of reaction.

Without catalyst - No change

16
Q

What is collision theory?

A
  • Particles must collide to react
  • Particles must collide with sufficient energy
  • Particles must collide at the correct orientation