P6.4 - Internal Energy Flashcards
What is a substance’s internal energy?
The total energy stored by the particles of a substance in their kinetic and potential stores
Where is a particle’s energy stored?
In kinetic stores by vibrating and in their potential stores due to their positions relative to each other
Does internal energy include gravitational potential energy?
No
How does heating a substance change its internal energy
By increasing the energy of its particles
When does the total potential energy of a substance change?
When it melts or boils
When does the total kinetic energy of a substance change?
When it’s temperature rises
What is the kinetic energy of particles due to?
Their individual motions relative to each other
How do you calculate the amount of energy needed to change the temperature of a substance by x degrees C? WITHOUT A CHANGE OF STATE
Change in energy = mass * specific heat capacity * change in temperature
What is the rule when using e = m * c * change in temp?
The substance cannot have a change of state, so you can’t use it to calculate how much energy is needed to change 80 degrees C water by 30 degrees C. It will pass the boiling point
When the ___ of a substance changes the ___ potential energy of its particles ___
Physical state, total, changes
Why when you heat a solid enough it melts?
Because its particles have gained enough energy to break appart from the structure and the forces holding them together
How does each particle in a solid vibrate?
Each particle of a solid vibrates about an average fixed position
How are the particles of a solid arranged?
In a fixed 3D structure
What happens to a liquid’s particles when it is heated?
Some of the particles gain enough energy to break away from the others and are in a gas state above the liquid
