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Flashcards in Energy Deck (9):

What is an endothermic reaction?

A reaction in which energy is taken from the surroundings (absorbs energy)


Recognise exothermic and endothermic reactions using temperature changes

- A rise in temperature is known as an exothermic reaction as heat energy is given out to the surroundings.
- A fall in temperature is known as an endothermic reaction as heat energy is taken in from the surroundings


Describe using a diagram a simple calorimetric method for comparing the energy transferred per gram of fuel combusted

Use of spirit burner or a bottled gas burner
Heating water in a copper calorimeter
Measuring the temperature change
Fair and valid tests


What reaction do bonds break?



What reaction are bonds made?



Equation for energy per gram

Energy per gram= energy released (in J) / mass of fuel burnt


Equation for energy transferred

Energy transferred= m x c x ∆T

m = mass of water heated
c = specific heat capacity (4.2J/g°C)
∆T = temperature change


Explain why a reaction is exothermic or endothermic using the energy changes that occur during bond breaking

- Chemical reaction that require more energy to break bonds than is released when new bonds are made are endothermic reactions
- Chemical reactions that release more energy when bonds are made than is required to break bonds are exothermic reactions


What is an exothermic reaction?

A reaction in which energy is transferred into the surroundings (releases energy)