Solids, Liquids and Gases New Flashcards
density definition
mass per unit volume of a material
density equation
ρ = m/V
why do gases have a lower density
particles in a gas are more spread out
method to measure density of a regular object
- Place the object on a digital balance and note down its mass
- Use either the ruler, Vernier callipers or micrometer to measure the object’s dimensions (width, height, length, radius) – the apparatus will depend on the size of the object
- Repeat these measurements and take an average of these readings before calculating the density
method to measure the density of irregular object
- Place the object on a digital balance and note down its mass
- Fill the eureka can with water up to a point just below the spout
- Place an empty measuring cylinder below its spout
- Carefully lower the object into the eureka can
- Measure the volume of the displaced water in the measuring cylinder
- Repeat these measurements and take an average before calculating the density
method to measure density of liquids
- Place an empty measuring cylinder on a digital balance and note down the mass
- Fill the cylinder with the liquid and note down the volume
- Note down the new reading on the digital balance
- Repeat these measurements and take an average before calculating the density
pressure
the concentration of a force or the force per unit area
pressure equation
P = F/A
A = cross sectional area
in what directions is pressure exerted by a fluid on a surface
all directions
pressure in a liquid formula
P = h x ρ x g
how are the particles in a solid packed and how do they move
-they are closely packed
-vibrate about fixed positions
shape and volume of solids
-definite shape
-definite volume
how are the particles in a liquid and how do they move
-particles are closely packed
-particles can flow over one another
shape and volume of liquids
-no definite shape - flow and take the shape of a container
-definite volume
how are the particles in a gas and how do they particles move
-particles are far apart
-particles move randomly in all directions
shape and volume of gases
-no definite shape- take the shape of the container
-no fixed volume - can expand to fill up an evacuated container
why are gases compressible
-large gaps between the particles
-easier to push the particles closer together than in solids or liquids
arrangement of particles in solids, liquids and gases
-solids are in a regular pattern
-liquids and gases are randomly arranged
energy of particles in solid, liquids and gases
solids have low energy
liquids have greater energy
gases have the greatest energy
what happens when a solid is heated to form a liquid
-thermal energy transfer take places and supplies the particles in the solid with energy in their kinetic store
-this breaks the rigid bonds(IMF)between the particles meaning they can now flow over each other
what happens when a liquid is heated to form a gas
-thermal energy transfer takes place and supplies the particles on the surface of the liquid with energy in their kinetic store
-this removes the bonds between the particles meaning they can move about randomly and spread far apart
what happens when there is an increase in kinetic energy in a system
-causes the temperature of the system to increase
-OR produces a change of state
what does higher temperature mean in terms of molecules
higher average kinetic energy of the molecules
method to investigate changes of state
- Place the ice cubes in the beaker (it should be about half full)
- Place the thermometer in the beaker
- Place the beaker on the tripod and gauze and slowly start to heat it using the bunsen burner
- As the beaker is heated, take regular temperature measurements (e.g. at one minute intervals)
- Continue this whilst the substance changes state (from solid to liquid)
why does the temperature of a substance remain constant throughout a state shift when being heated
-heat energy being produced is used up in changing the state of matter and for breaking numerous bonds or attractive forces
specific heat capacity
the amount of energy required to raise the temperature of 1kg of the substance by 1C per kg of mass (J/kgC)
how does the temperature of an object with a lower SHC change compared to an object with a higher SHC
-lower SHC object will heat up and cool down quickly
specific heat capacity of water
4200 J/kg C
specific heat capacity of alumnium
910 J/kg C
specific heat capacity of copper
390J/kg C
factors affecting how much the temperature of a system increases
-mass of the substance heated
-type of material
-amount of energy put into the system in the form of thermal energy
change in thermal energy of a substance equation
change in thermal energy = mass x specific heat capacity x change in temperature
ΔQ = m x c x ΔT
method to investigate specific heat capacity
- Place the beaker on the digital balance and press ‘zero’
- Add approximately 250 ml of water and record the mass of the water using the digital balance
- Place the immersion heater and thermometer in the water
- Connect up the circuit as shown in the diagram, with the ammeter in series with the power supply and immersion heater, and the voltmeter in parallel with the immersion heater
- Record the initial temperature of the water at time 0 s
- Turn on the power supply, set it at approximately 10 V, and start the stopwatch
- Record the voltage from the voltmeter and the current from the ammeter
- Continue to record the temperature, voltage and current every 60 seconds for 10 minutes
- Repeat steps 2-8, replacing the beaker of water for the solid block of aluminium and starting with recording its mass using the digital balance
-electrical energy = voltage x current x time
-SHC = gradient (when straight line)of energy supplied = y and temperature x mass = x
brownian motion
random motion of tiny particles in a fluid
at what angle do is there a net force on a container containing gas
right angle
why does a gas at concentration have a higher pressure
-more particles in a given area
-more frequent collisions with the container walls and a greater force
-higher force exerted per unit area
absolute zero definition
the temperature at which the molecules in a substance have zero kinetic energy
kelvin to celcius
θ/C = T/K - 273
celcius to kelvin
T/K = θ/C +273
what is a one degree increase in kelvin equal to in celcius
one degree increase in celcius
what is the lowest possible value of kelvin
- cannot be negative
relationship between temperature in kelvin and average KE of the molecules
proportional(directly)
how does the pressure of a gas change when it is compressed and expands
compressed - increases pressure
expands - decreases the pressure
why does gas have more pressure when it is in a lower volume
-particles travel the same speed, but the distance they travel is reduced when the container is smaller
-molecules hit walls of the container more frequently
-larger overall net force on the wall, increasing the pressure
why does gas at an increased temperature have more pressure
collide with the walls more often, creating increase in pressure
pressure law
pressure is directly proportional to temperature is the volume is constant
relationship between the pressure and temperature of two gases
p1/T1 = p2/T2
Boyle’s law
p x V = constant
unit of pressure
pascals(newton metres)
difference between pascals and joules(Nm)
pascals is newtons/metres, joules is newton x metres
relationship between pressure and volume
pressure and volume are inversely proportional to each other
relationship between the pressure and volume of two gases(Boyle’s law)
p1V1 = p2V2
