Specific Heat Capacity



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  • Different materials need different specific heat capacities . Some need more energy to increase their temperatures.
  • Materials which gain lots of energy in their energy store to warm up = transfer lots of energy when they cool down
  • Specific heat capacity = amount of energy needed to raise the temperature of 1kg by 1°C
  • Q=mc deltaT
  • Change in thermal energy (j) = mass (kg) X specific heat capacity (J/kg°C ) X temperature change (°C)
  • Practical to investigate specific heat capacities:
  • 1.Need a block of solid material with two holes in it ( for heater and thermometer)
    2. Measure mass of block, then wrap an insulating layer to reduce heat loss
    3.Measure initial temp of block and set potential difference (voltage) of the power supply to 10V. Turn on power supply and start a stop watch.
    4.Turn on power = current in circuit does work on heater = power supply → heaters thermal energy store → materials thermal energy store = materials temp to increase
    5. Block heats up = take temp and current readings every minute for 10 minutes. (current shouldn’t change)

    6. Turn off power supply after enough readings collected. Can calculate the power using power = potential difference X current. Then using energy transferred = power X time you can calculate how much energy transferred to the heater

    7. Plot a graph of energy transferred against temperature

    8. Find gradient of the straight part of the graph: change in temperature/change in energy transferred. Specific heat capacity = 1 / (gradient X mass of block)

    9.Repeat with different materials to compare Specific heat capacity

    How long have you…? (present perfect 4) Exercises


     

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    Use the information given to create questions beginning with ‘How long…?’

    • It is snowing.

    • The weather is shining.

    • John and Kate are married.

    • My brother has gone on holiday.

    • My aunty and uncle live in Canada.

    • My sister is a teacher.

    • I work at the chemist.

    • I’ve known Susan since I was a baby.

    • Jonathan is learning to speak to Mandarin.

     

     

     

    Fill in the missing gaps in the sentences using the present perfect (=has/have + past participle)

    • I have known Kate a long time.

    • My brother has been playing the piano he was 11 years old.

    • My mum and dad on holiday to America. They

    gone since last Sunday.

    • I Ben and Emma since primary school.

    We to the same primary and secondary school.

    • My sister learning to speak French because she
    is going to France next month.

     

     

    Use the appropriate words in the missing gaps.

    have you lived       lives      to

    has been       works        have known

    I have bought       have worked.

    • My sister in Spain. She is studying Spanish

    with her friend Rosie. I Rosie since I was 5.

    • Spencer like with Jamie. They have worked

    together for 2 years.

    • How long in Australia?

    • a new dress for prom.

    • He to Thorpe park.

     

     

    Challenge: Create 4 of your own questions beginning with ‘How long……?’

    1.

    2.

    3.

    4.

     

     

     

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