RP1 - Specifc Heat Capacity Flashcards

1
Q

Define the ‘Specific Heat Capacity’ of a substance.

A

The amount of energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celsius.

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2
Q

State the units for Specific Heat Capacity.

A

J/°C/kg

Joules/Degree Celsius/Kilogram

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3
Q

State the equation used to calculate the temperature change when a substance is heated. Give appropriate units.

A

● ΔE = m c Δ𝛉
● Energy (J), Mass (kg), Specific Heat
Capacity (J/kg/°C), Temperature (°C)

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4
Q

If the power of the heater being used isn’t given, how can you calculate it?

A

By connecting it in parallel with a voltmeter, and in series with an ammeter, and then applying the equation:

P= I x V

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5
Q

Why do the metal blocks used in the experiment have two holes in them?

A

One for is for the heater and one is for the thermometer.

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6
Q

What can be done to improve the reading given by the thermometer?

A

Add a few drops of water in the hole with the thermometer to improve the thermal contact and ensure even heating.

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7
Q

What reading do you record during the experiment and how frequently?

A

You record the temperature value every 10 minutes from when the heater is inserted and switched on.

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8
Q

What graph do you plot with the data?

A

A graph of temperature against work done by the heater.

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9
Q

How do you calculate the work done by the heater?

A

Using the equation:

Energy = Power of heater x Time

Where energy is equivalent to the work done.

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10
Q

Once the block has initially warmed up, describe the graph of temperature against work done by the heater that should be obtained.

A

It should be a linear relationship and so should produce a straight line.

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11
Q

If you start timing from when you switch on the heater, why may the graph not initially be linear?

A

There will initially be some thermal inertia whilst the block and heater warm up.

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12
Q

What does the gradient of the graph represent?

A

The inverse of the heat capacity for the metal block.

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13
Q

How do you obtain the specific heat capacity for the metal you are measuring?

A

Divide the inverse of the gradient by the mass of the metal block used.

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14
Q

What is the difference between heat capacity and specific heat capacity?

A

Specific heat capacity is the heat capacity measured for a mass of 1 kg.

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15
Q

Why should you wrap insulation around the outside of the metal block?

A

To reduce the heat loss to the environment and ensure the temperature reading is as accurate as possible.

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16
Q

What safety precautions should be taken when carrying out this experiment?

A

● Avoid touching the metal
● Use a heatproof mat
● Avoid spilling water near the power supply when adding drops to the thermometer hole