Unit 1 - Reaction Rates Flashcards

1
Q

Why does the reaction get slower as it proceeds?

A

The reactants are being used up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is relative rate calculated?

A

Rate = 1/time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What effect does increasing concentration have on a reaction rate?

A

It will increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why does increasing concentration increase the reaction rate?

A

There will be more reactant molecules & more collisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What effect does decreasing particle size have on reaction rate?

A

It increases reaction rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why does decreasing particle size increase the reaction rate?

A

It increases the surface area meaning more reactant particles are able to collide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What will a 10 degree rise In temperature do to reaction rate?

A

Roughly double it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is activation energy?

A

The minimum kinetic energy required by colliding molecules for a reaction to take place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What effect does increasing temperature have on reaction rate?

A

It increases reaction rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why does increasing temperature increase the reaction rate?

A

It increases the number of molecules which possess the necessary activation energy to react

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a catalyst?

A

A catalyst is a substance which speeds up a chemical reaction without being used up in the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does a catalyst work?

A

It provides an alternative pathway with a lower activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a homogeneous catalyst?

A

A catalyst which is in the same physical state as the reactants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a heterogeneous catalyst?

A

A catalyst which is in a different physical state to the reactants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does catalysis occur?

A

Active sites on the surface of the catalyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the three stages of how a surface catalyst works?

A

Adsorption
Reaction
Desorption

17
Q

What is a catalyst poison?

A

A substance which reacts with the surface of the catalyst so that it operates less effectively or not at all

18
Q

How does a catalyst poison work?

A

By occupying the active sites the poison stops the reactants occupying these sites

19
Q

Example of a catalyst poison?

A

Lead in leaded petrol poisoning the catalyst in catalytic converter

20
Q

Two examples of a catalyst?

A

Haber process - iron

Ostwald process - platinum

21
Q

How is average rate measured?

A

Reaction rate = change in variable/time

22
Q

What is an exothermic reaction?

A

A reaction in which energy is given out

23
Q

What is an endothermic reaction?

A

A reaction in which energy is taken in from the surroundings

24
Q

What is the activated complex?

A

An unstable arrangement of atoms formed at the maximum of the potential energy barrier during a reaction

25
What is the enthalpy of combustion?
The enthalpy of combustion is the amount of energy given out when 1 mole of a substance is completely burned in oxygen
26
What is the enthalpy of solution?
The enthalpy of solution is the amount of energy given out or taken in when one mole of a substance dissolves in water
27
What is the enthalpy of neutralisation?
The amount of energy given out per mole of water formed in a neutralisation reaction
28
What is the relative rate?
The rate at any one particular point in time
29
Give 2 reasons it is important to control the rate of a reaction
Make the processes economically viable and safe.
30
What is the collision theory?
For a chemical reaction to take place the reactant molecules must collide with enough energy and at the correct collision geometry.
31
List 4 ways to increase the rate of a reaction
increase temperature increase concentration decrease particle size use a catalyst
32
what is enthalpy?
a measure of the energy stored in a chemical