Particle Model of Matter

• What is density defined as?

  mass per unit volume of a material
• What is all matter made of?

  Very small particle called atoms
• What are the particles like in solid?

  The particles are closely packed

  The particles vibrate about fixed positions
• What do solids have?

  Definite shape and volume
• What are particles like in liquids?

  The particles are closely packed

  The particles can flow over one
• What do liquids have?

  no definite shape but definite volume
• What are the particles like in gas?

  The particles are far apart

  The particles move randomly
• What do gases have?

  No definite shape or volume
• Why are gases highly compressible?

  There are large gaps between the particles

  It is easier to push particles closer together than in solids or liquids
• Solid, Liquid, Gas summary table

  
• Why do liquids have a different density to solids even though they both have the molecules are tightly packed together?

  In a liquid the molecules have enough energy to push past each other
• Why do gases have a lower densities than solids or liquids?

  Because the molecules are widely separated
• Experiment 1: Measuring the Density of Regularly shaped objects variables

  Independent - type of shape/volume

  Dependent - mass of the object
• Diagram of apparatus

  
• Method for this practical

  1. Place the object on a digital balance and note down its mass

  2. Use either the ruler, Vernier measurements or micrometer to measure the object's dimensions (width,height, length, radius) - the apparels will depend on size of the object

  3. Repeat these measurements and take an average of these readings before calculating the density
• Experiment 2: Measuring the density of irregularly shaped objects variables

  Independent- different irregular shapes/ mass

  Dependent - volume of displaced water
• Apparatus for measuring the density of irregular objects

  
• Method for this experiment

  1. Place the object on a digital balance and note down its mass

  2. Fill the eureka can with water up to a point just below the spout

  3. Place an empty measuring cylinder below its spout

  4. Carefully lower the object into the eureka can

  5. Measure the volume of the displaced water in the measuring cylinder

  6. Repeat these measurements and taken an average before calculating the density
• Experiment 3: Measuring Density of Liquids variables

  Independent - Volume of water added

  Dependent - mass of cylinder
• Apparatus for determining the density of a liquid

  
• Method for this practical

  1. Place an empty measuring cylinder on a digital balance and note down the mass

  2. Fill the cylinder with the liquid and note down the volume

  3. Note down the new reading on the digital balance

  4. Repeat these measurements and take an average before calculating he density
• Systematic errors of all these experiments

  Ensure the digital balance is set otherwise zero before taking measurements
• Random errors of all these experiments

  Ensure to take repeat readings and calculate an average to keep this error to a minimum

  Place the irregular object in the displacement can carefully, as dropping it from a height might cause water to splash which will lead to an incorrect volume reading
• Changes of state are ________

  reversible
• What are the six changes of state?

  Melting

  Boiling

  Condensing

  Freezing

  Subliming
• Diagram showing the arrangement and motion of different states of matter

  
• Why does the mass of the substance not change when chagrin state?


  The number of particles in a substance doesn't change when it changes state

  Therefore, the mass of the substance doesn't change
• What do molecules within a substance have energy in?

  Their kinetic store and potential store
• What is the internal energy of a system stored in?

  The atoms and molecules that make up the system
• What does an increase in internal energy from heating cause?


  A change in state
• Heating/cooling graph of a substance showing the energy changes as temperature is increased/decrease

  
• What is the specific heat capacity?

  The amount of energy required to increase the temperature of 1kg of a substance by 1oC
• What is specific latent heat?

  The amount of energy needed to causes a change of state
• Specific heat capacity vs Specific Latent Heat table

  Specific heat capacity involved in changing temperature but specific latent heat is involved in changing state

  In specific heat capacity is the same for the same material at all temperatures

  In specific latent heat is different values for the same material depending on the change of state
• What are molecules in a gas in at high speeds?

  Constant random motion
• Is the average kinetic energy higher when the gas is hotter and vice versa?

  Yes it's hot
• When the temperature of a gas increase what happens to the average speed of the molecules?

  Also increases
• When does kinetic energy of molecules increase?

  If its volume remain constant
• What does a gas with higher pressure have?

  More frequent collision on the container walls
• What happens to the pressure if the gas is heated up?

  The pressure increase because the molecules will travel at a higher speed which mean they will collide with the walls more often