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Flashcards in Energy Deck (9)
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1
Q

What is an exothermic reaction?

A

One which gives out energy to the surroundings, usually in the for of heat and usually shown by a rise in temp.

2
Q

What is an endothermic reaction?

A

One which takes in energy from the surroundings, usually in the form of heat and usually shown by a fall in temperature

3
Q

During a chemical reaction, old bonds are [ ] and new [ ] are formed

A

broken

bonds

4
Q

What is bond breaking? (Endo/Exo) Why?

A

Energy must be supplied to break existing bonds = endothermic

5
Q

What is bond formation? (Endo/Exo) Why?

A

Energy is released when new bond are formed = exothermic

6
Q

In an endothermic reaction, the energy required to break bonds is [ ] than the energy required when new bonds are formed

A

greater

7
Q

In an exothermic reaction, the energy required to break bonds is [ ] than the energy required when new bonds are formed

A

less

8
Q

How do you measure the amount of energy released by a chemical reaction?

A

By taking the temp of the reagents, mixing them in a polystyrene cup and measuring the temp. at the end of the reaction

9
Q

What is the biggest problem with energy measurements? How can you reduce this?

A

The amount of energy lost to the surroundings
By putting the polystyrene cup into a beaker of cotton wool to give more insulation, and putting a lid on the cup to reduce energy loss by evaporation