Classified past paper of Unit 5: Solids, Liquids and gases.
EDEXCEL IGCSE past papers for code 4PH1/4PH0.
The paper has question from paper 1 and 2 from higher tier.
UNIT 5: Solids, Liquids and gases, classified past papers link for download is given below:
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Notes can be found on this link in PDF format. Visit notes page Here
Mainly covering:
Density: Concept and formula related questions,Develop relationship between Density, volume and mass using formula (Density= Mass/Volume).
Experimental questions related to density measurements of regular and irregular solids.
Understand different equipment needed ; Electronic balance,vernier calipher and test-tube filled with water-(for measuring volume of irregular solids),If there is more information needed on this topic,Feel free to visit the notes page to understand more detailed experiments.
Practical to calculate the density of a Solid material:
Measure the mass using
suitable equipment (electronic balance)
Measure the volume. Volume of a regularly shaped solid can be measured using ruler. For irregularly shaped objects, immerse the object in water-shown below.
Use the formula and find the
density of a material.
Practical to calculate the density of a Liquid material:
a) Record the mass of an empty 100 ml measuring cylinder using
electronic balance.
b)
Then pour 20 ml of liquid in
the cylinder and record the mass of cylinder with liquid.
c)
Calculate the mass of the
liquid by subtracting empty cylinder value from the 20 ml liquid. (Always
measure from the eye level-shown below in picture).
d) Add 20 ml more to the liquid a repeat the process till 5 pair of
values have been achieved.
Then calculate the density and take the average.
Develop relationship between pressure, force and area and understand the use of formula Pressure=force/area.Understand the indirect relatonship
Difference between structural arrangement of particles in solids, liquids and gases:
Solid: Atoms are packed regularly structure and cannot move. They are in fixed shape but they can vibrate. The atoms are held together by strong forces. Density is the highest compared to liquid and gases as there is a lot of mass in small volume same as liquid.
Liquid: Atoms are close together and forces between the molecules keep them closer together. Atoms move from one place to another. This allows change of shape to fit into the shape of container. Molecules are closer together which makes it harder to compress. Density is higher than gases.
Gas: The atoms are far apart and the forces between them is very small. Atoms are in random constant motion. Gases can fill any volume and can be compressed easily than solids and liquids. Density is the lowest compared to solid and liquid. There will be least amount of mass in the same volume of sample. Density of air is more than that of hydrogen as air contains atoms of nitrogen and carbon which are more in mass.
Barometer related questionsAtmospheric pressure:
Measured using mercury barometer, how we can measure atmospheric pressure using a mercury. A small space of vacuum above barometer in order to support the large atmospheric pressure exerted at 76 cm long mercury. Pressure at X = pressure at Y, in the diagram.
When large pressure is
exerted using a small area the pressure is exerted in the direction of force. Example:
hitting nail with hammer, pushing a piston filled with liquid downwards
increases the force in the liquid molecules.
Specific Heat Capacity versus Specific Latent Heat:
Specific heat capacity:
The SHC of substance is the heat energy required to raise the temperature of one kilogram of the substance by one degree Celsius. The Specific heat capacity of water is more than that of solid, which is why humans are kept safe. The temperature of a system depends on: mass of the substance being heated, what is the substance made up of.
Specific heat capacity Joules per kilogram per Celsius/Kg°C
Water has high specific heat capacity;
this means a lot of energy is needed to heat up the substance and a lot of
energy is given out when a substance is cooled. Water helps in thermal
regulation of blood.
It is also used to keep
houses warm as a central heating system pumps hot water around the house, This
hot water transfers energy through radiators.
Specific latent heat (L):
Energy required to change
state of matter without increase in temperature. Unit is Joules/Kg.
Defined as: The amount of heat energy required to change the state
of 1 kg of substance with no change in temperature.
Specific latent heat of fusion: Energy required to change the
state of 1 kg of solid to liquid with no change in temperature (or vice-versa).
It is melting or freezing.
Specific latent heat of vaporisation: Energy required to change the state of 1 kg of liquid to gas with no change in temperature (vice-versa). It is vaporising or condensing.
The small difference between specific heat capacity and Specific latent heat is that:
Specific heat capacity is
used to measure change in temperature within same state, whereas specific
latent heat is used to change the state without change in temperature.
The particle model of
gases
Particle model theory suggest
that:
1.
The particles of gas are in
constant random motion-known as Brownian motion
2.
The particles collide with
each other and walls of container without transferring kinetic energy.
3.
Temperature of gas is related
to average kinetic energy of molecules.
4.
Kinetic energy of molecules
increases, temperature of gas increases.
Gas pressure:
Force exerted by gas
molecules onto sides of container. Each particle exerts a force on wall at
right angles to the side. When temperature of a fixed volume of gas is increased,
the pressure of gas increases. The increase of temperature causes speed of
particles to increase. So, particles hit walls of container with greater force,
the number of collisions increases and so the pressure increases.
Absolute zero:
The pressure of gas is measured a temperature from 0°c to 100°C. The pressure rises from 100 kPa to 137 kPa.If the temperature is reduced to below 0°C then at −273 °C, gas pressure is observed to be zero. This means there is no movement of particles taking place and when there is no movement, there is no force exerted. Hence −273 °C, is the absolute zero mark.
The Kelvin scale;
The kelvin
scale begins at absolute zero point which I −273 °C so: 0 K= −273 °C. There is no degree mark for
kelvin scale.
The kinetic
energy of molecules is directly proportional to kelvin scale. As the
temperature on kelvin scale increases, kinetic energy on molecules also
increases.
There is no
temperature lower than 0 K, this is why there is an absolute temperature scale
to predict temperature scale.
Converting Celsius to kelvin
= +273.
Converting kelvin to Celsius
= -273.
Boyle’s
law
Pressure of gas changes when
temperature is made constant.
Example of compressing the
piston (decreasing the volume): will increase the pressure as frequency of
collision increases and expanding the piston (increasing the volume) will
decrease the pressure. When a frequency of collision increases. The particles
exert forces at right angles to the surface and so the pressure increases.
For a fixed mass of gas at
constant temperature.
P1V1=P2V2
This is known as Boyle’s law.
The ratio of pressure to temperature (in K) for gas is always same.
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