P3 - Particle Model Of Matter Flashcards
Equation for density
Density (kg/m3) = mass (kg) \ volume (m3)
Required practical - density of a regular solid object (3)
- Use a balance to measure its mass
- measure the length, width and height - calculate the volume
- Calculate density using the equation
Required practical - density of a irregular solid object (4)
- Find the volume - by submerging it in a eureka can filled with water
- The water displaced by the object will be transferred to the measuring cylinder
- Record the volume of water in cylinder. This is the volume of the object
- put the object’s mass and volume into the density formula
Diagram for the solid model
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Diagram for the liquid model
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Diagram for the gas model
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Explain the solid state of matter in terms of arrangement of atoms or molecules (2)
- Strong forces of attraction hold the particles close together in a fixed, regular arrangement
- The particles don’t have much energy so they can only vibrate about their fixed positions
Explain the liquid state of matter in terms of arrangement of atoms or molecules (3)
- There are weaker forces of attraction between the particles
- The particles are closer together, but can move past each other, and form irregular arrangements
- They have more energy than the particles in a solid - they move in random directions at low speed
Explain the gas state of matter in terms of arrangement of atoms or molecules (3)
- There almost no forces of attraction between the particles
- The particles have more energy than in liquids and solids
- free to move, and are constantly moving with random directions and speeds
What happens to the mass when substances change state
The mass is conserved
What are changes of state
Are physical changes which differ from chemical changes because the material recovers its original properties if the change is reversed
Internal energy (2)
- Is the energy stored inside a system by the particles that make up the system
- Is the total kinetic energy and potential energy of all the particles that make up the system
What happens when the energy of the particles is increased
This either raises the temperature of the system or produces a change of state
What does the increase in temperature depend on when the temperature of a system increases
- The mass of the substance heated
* The type of material and the energy input to the system
Equation for the change in thermal energy
Change in thermal energy (J) = mass (kg) x specific heat capacity (J/kg°C) x temperature change (°C)
Specific heat capacity of a substance
Is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius
Latent heat
Is the energy needed for a substance to change state
What happens when a change of state occurs
The energy supplied changes the energy stored (internal energy) but not the temperature
Specific latent heat of a substance
Is the amount of energy required to change the state of one kilogram of the substance with no change in temperature
Equation for energy for a change of state
Energy for a change of state (J) = mass (kg) x specific latent heat (J/kg)
Specific latent heat of fusion
Change of state from solid to liquid
Specific latent heat of vaporisation
Change of state from liquid to vapour
Heating graph
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Cooling graph
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Molecules of gas
- Are in a constant motion
* The temperature of the gas is related to the average kinetic energy of the molecules
What happens when the temperature of a gas ,held at a constant volume, is changed
The pressure exerted by the gas changes
How does the motion of the molecules in a gas is related to both its temperature and its pressure (3)
- If you increase the temperature of a gas, you transfer energy into the kinetic energy stores of its particles
- The higher the temperature the higher the average energy
- So as you increase the temperature of a gas, the average speed of its particles increase
The relation between the temperature of a gas and its pressure at constant volume (4)
- Increasing the temperature increases the pressure
- As the particles are travelling quickly, it means that they hit the sides of the container more often in a given amount of time
- Each particle has a larger momentum meaning they exert a larger force when they collide with the container
- These factors both increase the total force exerted on a unit area, and so increase the pressure
