Required Practicals - Specific Heat Capacity Flashcards
What materials are needed for the specific heat capacity practical?
1 kg copper, iron and aluminium blocks with two holes each
thermometer
pipette
30W heater
12V power supply
insulation to wrap around blocks
ammeter and voltmeter
4 mm leads
stopclock
mass balance
heatproof mat
What is the method for the specific heat capacity practical?
Measure and record the mass of the copper block in kg
Wrap insulation around the block
Place the heater in the larger hole in the block
Connect the ammeter, power pack and heater in series
Connect the voltmeter in parallel across the heater
Put a small amount of water in the other hole
Set the power pack to 12V. Switch it on.
Record the ammeter and voltmeter readings, these shouldn’t change during the experiment
Measure the temperature and start the stopclock
Record the temperature every minute for 10 minutes and record results in a table.
In the specific heat capacity practical, how do you calculate the power of the heater?
Power in watts = potential difference in volts x current in amps
How do you calculate the energy transferred by the heater?
Multiply the time in seconds by the power of the heater.
How do you calculate the specific heat capacity of the copper block in the specific heat capacity practical?
Plot temperature change against work done on a graph.
Draw a line of best fit.
Calculate the gradient of the graph by doing change in temp / change in work done.
Calculate specific heat capacity using 1/gradient.
What is the definition of specific heat capacity?
The amount of heat energy in J needed to increase the temperature of 1 kg of copper by 1 degree celcius.
What is the word equation for specific heat capacity?
Change in thermal energy (J) = mass in kg x specific heat capacity x temperature change.
After recording specific heat capacity of one block, what must you do?
Calculate specific heat capacity of other blocks of other metals by repeating the method.
What is the definition of specific heat capacity?
The amount of energy required to raise 1kg of a substance by 1 degree celcius.
What are the steps for finding specific heat capacity?
Place a beaker on a balance and press zero.
Now add substance and record the mass.
Place a thermometer and immersion heater into the substance.
Read the starting temperature.
Wrap the beaker in insulating foam.
Connect a joulemeter to the immersion heater.
Time the setup for 30 minutes.
Read the joules passed into the heater and the final temperature of the substance.
Why do we wrap a beaker in insulating foam in a specific heat capacity practical?
To reduce thermal energy transfer to the surroundings.
0.95 kg of oil was heated from 20 degrees to 75. 87258J of electrical energy passed into the immersion heater. Calculate the specific heat capacity of the oil. Give the answer to 1 dp.
1670.0 J/kg degrees celcius.
What are the sources of inaccuracy in calculating specific heat capacity?
Thermal energy may have passed out of the beaker into the air.
Not all thermal energy would be passing into the oil.
Incorrect reading of thermometer.
Thermal energy may not have been spread through the oil.
How do we solve the problem of thermal energy passing out of the beaker into the air? (specific heat capacity practical)
Use an insulator with a lower thermal conductivity.
How do we solve the problem of not all thermal energy having passed into the oil? (specific heat capacity practical)
Ensure that the immersion heater is fully submerged.
