As the container heats up, the gas molecules move faster
Faster motion causes higher kinetic energy and therefore higher internal energy
Author
Lindsay GilmourExpertise
Physics
The total energy stored inside a system by the particles that make up the system due to their motion and positions
Substances have internal energy due to the motion of the particles and their positions relative to each other
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As the container heats up, the gas molecules move faster
Faster motion causes higher kinetic energy and therefore higher internal energy
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The amount of energy required to raise the temperature of 1 kg of the substance by 1 °C
Low vs high specific heat capacity
Water of mass 0.48 kg is increased in temperature by 0.7 °C. The specific heat capacity of water is 4200 J / kg °C.
Calculate the amount of thermal energy transferred to the water.
Step 1: Write down the known quantities
Step 2: Write down the relevant equation
Step 3: Calculate the thermal energy transferred by substituting in the values
Step 4: Round the answer to 2 significant figures and include the units
ΔE = 1400 J
You will always be given the specific heat capacity of a substance, so you do not need to memorise any values.
However, it's useful to have the general idea that, the larger the number, the less the substance will increase in temperature for a given amount of heat.
You can see this for yourself in your own kitchen at home. Metal pans, which have a relatively low specific heat capacity get very hot, very quickly when put on the hob. Add water to the pan, which has a relatively high specific heat capacity and the water will take much longer to heat up.
Notice the units of specific heat capacity:
joules per kilogram per degree Celsius : J / kg °C
'per' means 'divided by'. We say 'per' in front of every value that is being divided by, hence 'per kilogram per degree Celsius'
to absolutely everything:
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Lindsay graduated with First Class Honours from the University of Greenwich and earned her Science Communication MSc at Imperial College London. Now with many years’ experience as a Head of Physics and Examiner for A Level and IGCSE Physics (and Biology!), her love of communicating, educating and Physics has brought her to Save My Exams where she hopes to help as many students as possible on their next steps.