Difference between heat and temperature
What is the difference between heat and temperature?
- This can be illustrated using a beaker of boiling water and a pipette:
Diagram to demonstrate the difference between heat and temperature
The effects of boiling water can be quite different depending on the quantity of water involved!
- You would get a very nasty burn if a whole beaker of boiling water spilled onto to your hand, but a drop of boiling water would cause little problem
- The water is at the same temperature in the pipette as in the beaker, but the beaker has a much higher heat content
- We say that temperature is a measure of the average kinetic energy of the particles whereas heat is a measure of the energy content of a substance
- The particles have kinetic energy because they are moving
- The faster they move the more energy they have and the higher the temperature of the substance
Conservation of energy
- Energy is a measure of the ability to do work
- There are many different types of energy and heat is only one of them
- During chemical reactions energy flows in and out of the reaction vessels
- Inside the reaction vessel is known as the system
- Outside the reaction vessel is known as the surroundings
Diagram to show energy and matter transfer in three types of system
Open systems are the most common for chemical reactions
- Most chemical reactions take place in open systems in which energy and matter can be exchanged with the surroundings
- In a closed system, energy can be exchanged with the surroundings but matter cannot
- Although energy can be exchanged between open and closed systems and the surroundings, the total energy of the process cannot change
- This is known as the Law of Conservation of Energy and is a cornerstone to understanding how chemical changes affect the energy flow in and out of systems
- An isolated system cannot exchange matter or energy with the surrounding and are rare
