Specific Heat Capacity Flashcards
States of matter
- solid
- liquid
- gas
- plasma
Plasma
A gas-like state made of charged particles (eg. ions and electrons). It has high energy. Examples are lightning, the Sun, or neon signs.
It acts like a gas
What to not do when drawing particle diagrams?
Particle-sized gaps
Or writing ‘free to move’
Gas —> Solid
Deposition
Solid —> Gas
Sublimation
Liquid —> Gas
Evaporation
Gas —> Liquid
Condensation
Solid —> Liquid
Melting
Liquid —> Solid
Freezing
Specific Heat Capacity
The energy needed to raise the temperature of 1kg of a material by 1 degree Celsius.
Water SHC
Water has a very high SHC
High SHC means…
A lot of energy is required to get it to a temperature. However, it can also retain energy or temperature very well
SHC measurement
J/kg °C
Water SHC
4200 J/kg °C
Oil SHC
2000 J/kg °C
Limestone SHC
910 J/kg °C
Glass SHC
840 J/kg °C
Iron SHC
460 J/kg °C
Copper SHC
390 J/kg °C
Copper SHC meaning
Copper has a low specific heat capacity, so less energy is required to input for it to get to the same end temperature when compared to another material. However, it will also lose temperature or heat much quicker.
Change in energy formula
Change in energy (J) = Mass (kg) x Specific Heat Capacity (J/kg °C) x Change in Temperature (°C)
Heat
Heat is the energy transferred from one object to another because of a temperature difference. It is measured in Joules (J).
Temperature
Temperature is a measure of how hot or cold something is, based on the average kinetic energy of its particles. It’s measured in degrees Celsius (°C), Kelvin (K), or Fahrenheit (°F).
Steel SHC
420 J/kg °C
Aluminium SHC
900 J/kg °C
Brass SHC
380 J/kg °C
Draw the SHC practical apparatus, labelled
N/a
Method of the SHC practical
- Measure the mass of the metal block using a mass balance, record in a table
- Insert the thermometer and heater into the block and connect to the power supply. Do not switch off the supply yet.
- Record the initial temperature in a table
- Switch on the circuit
- Heat the metal block for 10 minutes
- Switch off the circuit and record the final temperature reached by the thermometer and the energy transferred using the joulemeter.
- Calculate the temperature difference and use it to find the SHC of the metal block.
- Repeat the above procedure 3 times for reliability, and calculate an average of the SHC
- Repeat for each material
Is the value in the SHC practical an over or under estimate?
An overestimate as some of the energy supplied by the power supply is lost to the surroundings, but still counted by the joulemeter, being higher than expected.
In the SHC practical, would it be an under or over estimate?
It would be an overestimate, as some of the energy supplied by the power supply is lost to the surroundings, but still counted by the joulemeter, being higher than expected or an overestimate.
Stearic acid practical (Change of State)
- Collect a beaker, heatproof mat and thermometer
- One person per group then bring the beaker to the front to collect a boiling tube of Stearic acid
- Place the thermometer into the Stearic acid and stir, wait for the thermometer reading to settle- this will be your 0 reading
- Start a stopwatch and measure the temperature every 30 seconds
- Continue to stir gently (to maintain thermal equilibrium) with the thermometer, making sure you don’t remove the thermometer from the Stearic acid
- As the Stearic acid starts to solidify, stop stirring but continue to take temp vs time readings
What is the energy stored by particles in a system?
Internal energy. It is the total kinetic energy and potential energy of the particles.
Internal energy = KE + PE
Kinetic energy of internal energy
Due to the motion of the particles, the hotter it is, the greater KE.
Potential energy of internal energy
Due to the distance between particles, the further apart they are, the greater PE
