P3: Particle model of matter Flashcards
Describe the particle arrangement and motion of particles in a gas (3 main points)
- there are almost no forces of attraction between the particles
- travel freely in constant random motion
- high energy
Describe the particle arrangement and motion of particles in a solid (3 main points)
- strong forces of attraction
- closely fixed regular arrangements
- low energy thus only vibrate
Describe the particle arrangement and motion of particles in a liquid (3 main points)
- weaker forces of attraction (co. solid)
- random directions at low speeds
- more energy (co.solid)
Define density. State the relevant equation and its units
The mass per unit volume of a material
density= mass/volume
density: kg/m^3
mass: kg
volume: m^3
State the different states of matter in order of density of atoms
solid: most dense
liquid: denser than gas, less dense than solid
gas: least dense
Describe the practical to measure density of a solid object ( a regular object )
1) Determine the mass of the object using a balance
2) To work out the volume , measure the sides of the regular object and use the formula : width x height x length
3) Measure the density using using the relevant equation: Density= mass/volume
Describe the practical to measure density for irregular sized objects
1) Determine the mass of the object using a balance
2) To find the volume, fill a Eureka can with water
3) Submerge the object into the water. The water displaced by the object will be transferred to the measuring cylinder
4) Record the volume of water in the measuring cylinder. This is the volume of the object
5) Use the mass and volume values to find out the density using the formula
Describe the practical used to find the density of a liquid
1) Place a measuring cylinder on a balance and measure its mass.
2) Pour 10 cm3 of liquid into the measuring cylinder and measure its new mass.
3) Repeat these measurements until the measuring cylinder is full
4) For each measurement, use the formula to find the density
5) Take an average of your calculated densities for an accurate density value
What is always conserved when a substance undergoes a change of state?
Mass is conserved during a change of state.
How does a change of state differ from a chemical change?
the material retains its original properties when reversed
Define Evaporation
when a liquid changes into a gas state ( on the surface)
Define Sublimation
The direct changing of a substance from a solid state to a gas state, without passing through the liquid phase.
Define condensation
The changing from a gas state to a liquid state, when a
substance is cooled.
When water boils in an open pan, why does the mass of the pan of water appear to decrease?
- some of the water will evaporate and turn into water vapour
- this will leave the pan meaning the mass of the pan will decrease
- the mass of the system remains constant
Explain the processes involved when a bathroom mirror mists up
- hot water evaporates to form water vapour
- this water vapour lands on the cooler mirror
- the vapour condenses and returns to liquid state in the mirror’s surface
what is the internal energy of a substance?
- the energy stored by the particles
- the sum of the total kinetic and potential energies that make up a system