Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > Energy Changes (Year 11) - C7 > Flashcards

Energy Changes (Year 11) - C7 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What is an exothermic reaction

A

It is a reaction that transfers energy to the surroundings

This causes the temperature of the surroundings to go up

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

What is an endothermic reaction

A

It is a reaction that transfers energy from the surroundings

This causes the temperature of the surroundings to go down

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

Examples of Endothermic reactions

A

Melting and Boiling

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

Examples of Exothermic reactions

A

Combustion, Rusting and Neutralisation

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

What type of reaction is breaking bonds

A

Endothermic

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

What type of reaction is making bonds

A

Exothermic

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

What is the equation for energy change

A

Energy change = Energy of bonds broken - Energy of bonds made
If the answer is negative then the reaction is exothermic

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

Why do reactions need activation energy

A

To break the bonds in the reactants

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

What do fuel cells use

A

They use fuel and oxygen to produce electrical energy

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

What happens in hydrogen cells

A

Hydrogen is oxidised to produce water and electricity

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

What is the overall equation for hydrogen cells

A

2H 2 + O 2 = 2H20

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

What are the half equations for hydrogen cells

A

2H 2 + 4OH (N) = 4H20 + 4 electrons

O2 + 2H20 + 4 electrons = 4OH (N)
(N) = negative

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

What are the advantages of hydrogen fuel cells

A

No pollution
Can be used for a range of things
Don’t need to be electrically recharged

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

What are the disadvantages of hydrogen fuel cells

A

Hydrogen is highly flammable
Hydrogen is difficult to store
The hydrogen used in the cells can come from non-renewable sources

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

What is a battery

A

It is 2 or more cells connected together in a series

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

What does the voltage of cells depend on

A

Reactivity of metals
Electrolyte
Surface area of electrons

17
Q

What is an electrolyte

A

A solution that conducts electricity e.g. NaCl

18
Q

What are electrodes

A

They are 2 different metals which react together in an electrolyte which build up a charge difference
The positive metal is called the anode
The negative one is called the cathode

19
Q

What happens in non-rechargeable batteries

A

They use irreversible reactions

Once one reactant is used up, they stop producing a charge

Chemistry (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions