P6 - Molecules and Matter Flashcards
Describe how particles are arranged in a solid + movement and properties
- Close together in a regular pattern with strong forces of attraction
- They vibrate around a fixed point
- Generally high density
Fixed shape + volume
Describe how particles are arranged in a liquid + movement and properties
- Particles are still close together but in a irregular pattern
Weaker intermolecular forces - They can move and they fill the shape of the container
Not fixed shape so can flow but fixed volume
Describe how particles are arranged in a gas + movement and properties
- Particles are far appart and randomely arranged
- They move very rapidly at a range of speeds and randomly and collide with their container and other particles
- No fixed volume or shape
- Low density
Equation for density
ρ = m/v
Density = mass/volume
Density is in kg/m3
How to calculate the density for a regular and irregualr object
- Regular - find mass using a mass balance
- Find the volume by measuring the dimensions and multiplying them together
- Irregular - find mass by using a mass balance
- Fill eureka can with water until the water level is just below the spout
- gently lower the object in using a string and collect the water displaced in a measuring cylinder
- Volume of water displaced = volume of object
- To calculate density for both, you do ρ = m/v
What is internal energy
- The sum of kinetic energy and potential energy of all particles in a substance
What is evaporation
- When a liquid turns to a gas, but only on the surface of the liquid as only the particles on the surface have enough energy
What is the specific heat capacity of a substance and its equation
The amount energy needed to raise the temperature of 1kg of a substance by 1 degree celcius
Δ E = mcΔ θ
Describe a heating graph in terms of internal energy
- Temp of solid rises and increasing energy of particles (kinetic energy)
- Energy needed to change from solid to liquid to break bonds (potential energy)
- Temp of liquid rises and increasing energy of particles (kinetic energy)
- Energy needed to change from liquid to gas to break bonds (potential energy)
- Temp of gas rises
why is a scald from steam worse than a burn from water at the same temperature
- Steam has more internal energy due to increased potential energy from changing state
- This transfers more thermal energy to the person meaning a worse injury
What is the specific latent heat and equation
The amount of energy needed to change the state of 1kg of a substance without changing the temperature
For fusion, it is solid to liquid and for vaporisation, it is liquid to gas
Equation - E = mL
What does the increase in temperature of a system depend on
- Mass of the substance
- The material of the substance
- The energy input
What is the pressure of a gas
- Due to the particles colliding with the walls of the container
- It is the certain force exerted over a certain area
- The force produced acts at right angles to the surface of the container
Equation for pressure
p = F/A
What happens to the pressure when you increase temperature
- Particles have more kinetic energy
- There are more collisions per second
- These collisions are higher energy and transfer more energy
