C3, Energy from Reactions

HideShow resource information
What is needed to break bonds and what is released when bonds are made?
Energy needed to break bonds and energy is released when bonds are made
1 of 14
What do exothermic reactions do and what energy charge do they have?
They give out heat to the surroundings and have negative energy charge
2 of 14
Name 2 examples of exothermic reactions
combustion and neutralisation between acids and alkailis
3 of 14
When do energy changes happen?
When chemicals in solutions react, i.e. when acids and alkalis react
4 of 14
What does chemical reactions cause heat energy to do and what is energy transferred measured by?
Causes heat energy to be either given out or taken in from the surrounings and measured by a calorimetry
5 of 14
What do endothermic reactions do and what charge do they have?
They abosrb heat from the surroundings and make it cooler. It has positive energy charge
6 of 14
What can endothermic reactions be used for?
Electrolysis, ethanolic acid and sodium carbonate reacting and thermal decomposition of calcium carbonate in a blast furnace
7 of 14
In exothermic reactions, when is more energy released?
When new bonds are made than needed to break bonds
8 of 14
In endothermic reactions, when is more energy needed?
To break existing bonds than is released when new bonds are made
9 of 14
What do catalysts do to activation energy and name 2 benefits of this.
They lower activation energy. Means reactions happen quicker and it's more economical
10 of 14
Why is hydrogen as a fuel more economically friendly alternative to fossil fuels?
No carbon dioxide emmisions are released that could contribute to global warming
11 of 14
How does a hydrogen fuel cell work?
Hydrogen reacts with oxygen without burning. The energy released is used to generate electricity, used to drive an electric motor.
12 of 14
Why is reacting steam with coal or natural gas to form hydrogen a problem?
Coal and natural gas are non renewable resources
13 of 14
Name an advantage and dissadvantage of passing electricity through water to form hydrogen
Dissadvantage: Electricity is usually generated by fossil fuels, so pollution still occurs. Advantage: Sometimes electricity is generated by renewable resources, i.e. geothermal energy in iceland
14 of 14

Other cards in this set

Card 2

Front

What do exothermic reactions do and what energy charge do they have?

Back

They give out heat to the surroundings and have negative energy charge

Card 3

Front

Name 2 examples of exothermic reactions

Back

Preview of the front of card 3

Card 4

Front

When do energy changes happen?

Back

Preview of the front of card 4

Card 5

Front

What does chemical reactions cause heat energy to do and what is energy transferred measured by?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Energy of reactions/Exothermic and endothermic reactions resources »