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