Energy Changes Flashcards
What type of reaction involves a temperature increase
Exothermic
What type of reaction involves the temperature decrease
Endothermic
What’s an exothermic reaction?
A reaction that releases energy to the surroundings, the temperature will increase
What’s an endothermic reaction?
 a reaction that absorbs energy from the surroundings the temperature will decrease
What activation energy
The minimum amount of energy needed for a reaction to start
Give at least two examples of an exothermic reaction
Combustion respiration, self heating cans, handwarmers
Two. Examples of an endothermic reaction.
Photosynthesis, thermal, decomposition, sports injury pack
What is bond energy?
The energy requires to break a bond or the energy release when a bond is made
Using the idea of bond energies, explain why a reaction is exothermic
Because less energy is required to break the bonds that is released when bonds are made
How are chemical cells made?
Two different metals dipped in an electrolyte
How do the types of metals in a cell determine the potential difference that is generated?
The bigger the difference in reactivity the greater the potential difference
Why are some cells rechargeable?
They use reversible reactions
What is a fuel cell
A cell that uses a fuel and oxygen to generate electricity
Given advantage of a hydrogen fuel cell
Only produce water, or does not need to be recharged
Disadvantage of a hydrogen fuel cell
Hydrogen is highly flammable and is difficult to store or hydrogen, often acquired from nonrenewable sources
