P6 Flashcards
What is density?
The meaure of compactness of a substance. It relates to how much space it takes up
Whats the symbol for density?
P (greek letter)
1g/cm3 =
1000kg/m3
Whats the equation for density?
Mass(kg)/volume(m3)
What does the density of an object depend on?
What its made of and how the particles are arranged
How are particles in a dense material packed?
Packed tightly together
How are particles in a less dense material arranged?
Spread out and if you compressed them it will be close together
Arrangements of a solid?
- Strong forces of attraction hold the particles together in a fixed position.
- They don’t have that much energy so they vibrate in fixed positions
- The density is the highest as the particles are close together
Arrangements of a liquid?
- weaker forces of attraction between the particles
- the particles are close together but can move past each other and form irregular arrangements
- Move in random directions at low speeds
- Liquids are less dense than solids
Arrangements of gases?
- No forces of attraction between particles
- They have most energy between 3 states
- They are free to move in random directions at high speeds.
How do you measure the density of a solid?
1) Use a balance and measure the mass
2) If a regular solid mesusre l,w,h and find volume by using the formula
3) for irregular find it by submerging a eureka can filled with water. The water displaced put in a measuring cyclinder
4) Record the volume by mesuring the water in the measuring cyclinder
How do you find density of a liquid?
1) Place measuring cylinder on balance and put on 0
2) Pour 10 ml of liquid in measuring cylinder and record the liquids mass
3) Pour another 10ml and repeat it until it is at the top and record the volume
4) For each volume use the formula
5) Finally take an average of the liquids
Equation for specific heat capacity.
∆E=mc∆T
What is internal energy?
Energy stored by the particles making up a system
What happens in a system?
Vibrate or move around
Why else do they have energy in their potential energy stores?
Due to their positions
What does heating the system do?
Transfers energy to its particles they gain energy in kinetic stores and move faster increasing their internal energy
When does a change of state occur?
If the substance is heated enough the particles will have enough energy in their kinetic stores to break bonds holding them together
What happens when you heat a liquid?
Boils or evaporates and becomes a gas
Whats a change of state?
A physical change. Same substance different form
What happens when you reverse a change of state ?
The substance will return to its original form with original properties
What does it mean when it says mass is conserved?
The number of particles doesn’t change theyre arranged differently
Whatbare the flat spots in a graph?
Where energy is being transfered
What is latent heat?
The energy needed to change the state of a substance
What is the specific latent heat?
The energy needed for a1kg mass to change state without changing its temperature
What is cooling in SHC?
Specific latent heat is the energy released by changing state
What is the specific latent heat between solid and liquid?
Specific latent heat of fusion
What is the specific latent heat between liquid and gas?
Specific latent heat of vaporisation
Whats the formula for specific latent heat?
E=mL
What does higher the temperature mean?
Higher the average energy
Why is it when you increase the temeprature of a gas the average speed of its particles increase?
1/2mv2
What does colliding gas particles create?
Pressure
What speeds do gas particles move?
High speeds and bang in to eachother
When happens if the temperature is constant and you increase the volume?
Particles get more spread out and hit the walls less often. The gas pressure decreases
Whats the equation that links pressure and volume?
pV
What can a change in pressure cause?
A change in volume
What does a pressure of gas cause?
A net outwards force at right angles to the surface of its containers
What happens when a balloon is released into the air?
it rises. Atmospheric pressure decreases with height so the pressure outside the balloon decreases. This causes the balloon to expand until the pressure inside drops to the same as the atmospheric pressure
What does doing work mean?
Transfer energy by applying force
