Practical- specific heat capacity

• EQUIPMENT LIST:

  A) Thermometer

  B) Immersion heater

  C) Voltmeter

  D) potential difference

  E) Ammeter

  F) current

  G) Power

  H) balance

  I) Stopwatch

  
• Specific Heat Capacity of Water

  Aim: to determine the specific heat capacity of water by measuring the energy required to increase the temperature by 1°C

  Method:

  1. Place the beaker on the balance and zero
  2. Add 250 ml of water and record the mass
  3. Place the heater and thermometer in the water
  4. Connect up the circuit
  5. Record the initial temperature of the water at time 0 s
  6. Turn on the power supply, set at approximately 10 V, and start the stopwatch
  7. Record the voltage and current
  8. Continue to record the temperature, voltage and current every 60 seconds for 10 minutes
• Specific Heat Capacity of Water

  Analysis of Results

  • Calculate the energy supplied each minute using the formula:Electrical energy (J) = voltage (V) × current (A) × time (s)
  • Calculate the temperature change by subtracting the temperature at time 0 s from the temperature recorded each minute
  • Calculate the average mass of the water by adding the mass at the start and the mass at the end and then dividing the total by two
• Obtaining a Temperature-Time Graph for Melting Ice

  Aim: to plot a graph of the temperature of ice, against time, as it is heated to water

  Method:

  1. Place some ice in a beaker so it is about half-full
  2. Place a thermometer in the beaker
  3. Place the beaker on a tripod and gauze and slowly start to heat it using a bunsen burner
  4. As the beaker is heated, take regular temperature measurements (e.g. at one minute intervals)
  5. Continue this whilst the substance changes state (from solid to liquid)
  6. The results can then be plotted on a graph
• Evaluating the Experiments

  Systematic Errors:

  • Ensure the digital balance is set to zero
  • Determine the efficiency of the immersion heater before experiments
  • Remember to only take gradients on the straight-line region
  • Before this point the energy supplied is being used to heat the immersion heater itself

  Random Errors:

  • Stir the ice water constantly whilst heating in experiment 2
  • When the current or voltage values appear to be changing between two values next to one another then be consistent in choosing the higher value
• Safety Considerations

  • The immersion heater will get very hot
  • Make sure not to touch it, and have a heatproof mat ready to place it on
  • Make sure that the immersion heater is connected to a direct current supply
  • The beaker may become unstable with an immersion heater and thermometer resting in it
  • If you feel this is the case then use a clamp stand to hold both
  • Wear goggle while heating water
  • Make sure to stand up during the whole experiment, to react quickly to any spills