Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry > Book 2 - Rates, Salts and Electrolysis > Flashcards

Book 2 - Rates, Salts and Electrolysis Flashcards

(86 cards)

Start Studying
1
Q

What is the rate of reaction?

A

The speed of a chemical reaction.

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

How do you work out the rate of a reaction?

A

Amount of reactant used/Time
Or
Amount of product formed/Time

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

The rate of a chemical reaction can be … Or …

A

Very fast or very very slow.

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

Give an example of a very fast chemical reaction.

A

An explosion

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

Give an example of a very slow chemical reaction.

A

Rusting

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

What is collision theory?

A

For a chemical reaction to occur, the reacting particles must collide with each other.

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

Does every collision produce a reaction?

A

No

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

What does the rate of collision theory depend on? Name 2 things

A
  • The frequency of collisions between particles

- The energy with which the particles collide

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

For a collision to be successful, the colliding particles must have the necessary what?

A

Activation Energy (Symbol Ea)

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

What is the activation energy?

A

The minimum energy needed to start a reaction.

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

For a reaction to start what is needed as well as the activation energy?

A

The particles need to collide with the correct orientation.

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

What happens if the number of successful collisions between the reactants increases?

A

The reaction will speed up.

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

What factors will affect the rate of a reaction?

A
  • Surface area of a solid reactant
  • Concentration of a solution
  • Temperature
  • Light
  • Catalyst
  • Pressure of a gas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What can a graph show about the rate of a reaction?

A
  • Reaction is fast at the start because there is a large number of particles reacting
  • Reaction slows down because there are less reactant particles than at the beginning
  • It stops because all the reactant particles had been used up.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How can the rate of reaction be measured?

A

Measuring the rate of reaction means measuring the change in the amount of a reactant or the amount of a product.

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

How can the rate of reaction be calculated from a graph?

A

Rate of reaction = y/x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the Maxwell-Boltzmann theory?

A

They analysed the distribution of energies of molecules in a sample of a gas. They found that the molecules don’t all have the same energy. They found that some molecules had more energy than others.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does increasing the temperature affect the reaction rate?

A

At a higher temperature it increases the amount of molecules with activation energy because there are more successful collisions per second. Which means that the rate of reaction increases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What will a graph look like after the temperature has been increased for reaction times?

A

The graphs peak will move to the right.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a catalyst?

A

A catalyst increases the rate without being used up or changed chemically.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does a catalyst do?

A

A catalyst provides and alternative route with a lower activation energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Overall what is the effect of a catalyst?

A

Therefore with a catalyst there are more molecules with energy, causing more successful collisions per second. So the rate of reaction increases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

If there is a lot of water and little solute, what is the solution?

A

Dilute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If there is a large amount of solute in a small amount of water, what is the solution?

A

Concentrated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is a solute?
A substance that is dissolved in a liquid to make a solution.
26
Why do reaction rates increase as the concentration increases?
Before two particles react, they must meet. This is more likely to happen in a concentrated solution than in a dilute one because there more particles are in the same volume which increases the frequency of collisions.
27
Why does a higher pressure increase reaction rates?
The same number of particles are squeezed into a smaller volume, meaning the closer the particles are together the higher the chance they have of colliding.
28
Why does increased surface area, increase the rate of the reaction?
A larger surface area increases the frequency of collisions between reactants. E.g When a block of a substance is reacted with a liquid, only the particles exposed at the surface of the block can react whereas if the substance were to be powdered the surface area increases dramatically as all those particles are able to react, increasing the rate of the reaction.
29
What is an enthalpy change?
The energy change which occurs in a chemical reaction. It the symbol 🔼H and its units are kJmol-1
30
What is an exothermic reaction?
Energy in the form of heat is given out to the surroundings.
31
What does an exothermic reaction result in?
An increase in temperature.
32
Is the sign positive or negative after an exothermic reaction?
Negative
33
For an exothermic reaction, do you have to put more energy in or do you get more energy out?
You get more energy out when new bonds form in the products than you had to put in to break the bonds in the reactants.
34
Name four types of reactions that are examples of exothermic reactions.
- Combustion reactions - Neutralisation reactions - Redox reactions - Hydration of anhydrous salts
35
What is an endothermic reaction?
Energy in the form of heat is taken in from the surroundings.
36
What does an endothermic reaction result in?
Decrease in temperature
37
Is the sign positive or negative after an endothermic reaction?
Positive
38
For an endothermic reaction, do you have to put more energy in or do you get more energy out?
You have to put more energy in to break the bonds in the reactants than you get out when new bonds form in the products.
39
Name three types of reactions that are examples of endothermic reactions.
- Thermal decomposition reactions - Some reactions between carbonates/hydrogen carbonates and acid - Dehydration of hydrated salts
40
What is a reversible reaction?
A reaction is reversible if both forward and reverse reactions can take place.
41
In a reversible reaction what is the difference between the reactions that take place?
One direction is exothermic and the other is endothermic.
42
Why are catalysts used in industry?
The cost of precious metal is often less than the extra cost of energy.
43
Why are catalysts better for the environment?
Fossil fuels are used to produce the energy for reactions without catalysts.
44
How can catalysts be harmful for the environment?
Transition metals used as catalyst are often toxic and can escape into the environment.
45
What type of reaction is oxidation?
Exothermic
46
What are acids?
Substances that produce H+ ions when added to water.
47
What is an alkali?
A soluble hydroxide that produces OH- ions when added to water.
48
What are bases?
Substances that neutralise acids.
49
How is acidity measured?
Using a universal indicator with a pH scale.
50
What are soluble hydroxides?
Alkali
51
What are metal oxides and hydroxides?
Bases
52
What pH is pure water?
7 - neutral
53
What colour does universal indicator turn for acidic substances?
Red
54
What colour does universal indicator turn for alkali substances?
Purple
55
What is produced when a metal and acid react?
Salt and hydrogen gas
56
What is produced when an acid reacts with a base?
Salt and water
57
What kind of reaction occurs between acids and bases?
Neutralisation
58
What is the equation of neutralisation in terms of ions?
H+(aq) + OH-(aq) ----> H2O(l)
59
What is a precipitation reaction?
Combining two solutions that contain different soluble salts which react to make an insoluble salt.
60
How are precipitate reactions used in water treatment?
Raising the pH makes insoluble metal hydroxides precipitate out.
61
What is electrolysis?
Breaking down a substance using electricity.
62
What type of substances can be electrolysed?
Ionic compounds can be electrolysed when they are molten or in a solution.
63
What is made from electrolysis?
Positive ions moves to the cathode while negative ions move to the anode.
64
What is the electrolyte?
The substance being broken down.
65
What are electrodes made of?
Inert substances such as graphite or platinum.
66
Why are electrodes made from unreactive materials?
So the electrodes don't react with the electrolyte or the products of electrolysis.
67
What happens to the ions in electrolysis?
Negative ions are oxidised. Positive ions are reducted.
68
How does water affect the products of electrolysis?
- The less reactive element between hydrogen and the metal is produced at the cathode. - At the anode, oxygen is often produced from the discharged hydroxide ions.
69
What is reduction?
Gaining electrons
70
What is oxidation?
Losing electrons
71
How is aluminium obtained from aluminium oxide?
Aluminium oxide is electrolysed.
72
Why is cryolite used in aluminium extraction?
Aluminium oxide is mixed with cryolite to lower its melting point.
73
What forms at the cathode during aluminium extraction?
Molten aluminium
74
What is formed at the anode during aluminium extraction?
Oxygen which reacts with the carbon electrodes making carbon dioxide.
75
Why are the carbon electrodes regularly replaced?
The carbon reacts with oxygen so burns away very quickly.
76
What type of salt does hydrochloric acid make?
Chlorides
77
What type of salt does sulphuric acid produce?
Sulphates
78
What type of salts does nitric acid make?
Nitrates
79
If a metal is very reactive, what is used instead?
Their form as a metal oxide.
80
What do strong acids have?
A high concentration of H+ ions.
81
What do weak acids have?
A low concentration of H+ ions
82
What do strong alkalis produce?
A high concentration of OH- ions.
83
What do weak alkalis produce?
A low concentration of OH- ions.
84
When are salts formed?
Formed by the reaction of an acid with a metal, base or alkali, metal or carbonate.
85
What type of salts are soluble?
- All sodium, potassium and ammonium salts - All Nitrates - All sulphates - All chlorides, bromides and iodides
86
What type of salts are insoluble?
- All carbonates | - All hydroxides

Chemistry (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions