year 9 internal energy

• What concept relates internal energy to temperature?

  Specific heat capacity
• What is internal energy?

  Total energy stored by particles in a substance
• What are the two parts of internal energy?

  Potential energy stores and kinetic energy stores
• What types of potential energy stores are mentioned?

  Gravitational and elastic potential
• Why can potential energy stores be ignored in this context?

  They are not related to temperature
• What happens to kinetic energy when a substance is heated?

  It increases, raising the internal energy
• How is temperature defined in relation to internal energy?

  Measure of average internal energy of a substance
• What does a higher internal energy indicate about a substance's temperature?

  It results in a higher temperature
• What is the specific heat capacity of water?

  4200 joules per kilo per degree Celsius
• How much energy is needed to heat 1 kg of mercury by 1°C?

  139 joules
• How much energy is needed to heat 1 kg of water by 1°C?

  4200 joules
• What does specific heat capacity represent?

  Energy needed to raise temperature of 1 kg by 1°C
• What happens when 1 kg of water cools by 1°C?

  It releases 4200 joules of energy
• What is the equation for change in internal energy?

  Change in internal energy = mass × specific heat capacity × change in temperature
• What does the symbol $\Delta$ represent in the equation?


  Change in a quantity
• What does the symbol $\theta$ represent in the equation?


  Temperature
• How do you find the change in temperature?

  Energy divided by mass times specific heat capacity
• What is the mass of water in kilograms if it is 800 grams?

  0.8 kilograms
• How do you convert 20 kilojoules to joules?

  20,000 joules
• What is the temperature change when 20,000 joules is added to 0.8 kg of water?

  1. 95 degrees Celsius
• What is the final temperature of water if the initial temperature is 20 degrees Celsius and the temperature change is 5.95 degrees?

  25.95 degrees Celsius
• Why might the actual temperature increase be less than calculated?

  Some energy is lost to surroundings
• What should be done to minimize energy loss in an experiment?

  Use a lid and insulate the container
• What should you do if you liked the video?

  Give it a like and subscribe
• particles in a substance are held together by chemival bonds- potential energy is stored in these bonds
• the stronger the bonds (e.g. in a solid) the more potential energy that is stored in them
• kinetic energy in particles stays constant when the temperature is constant and there are no external influences affecting the system.
• external influences could be: pressure changes, temperature changes, light intensity, pH, salinity, and oxygen levels