Internal energy

• What concept relates the internal energy of an object to its temperature?

  Specific heat capacity
• What is internal energy?

  It is the total energy stored by the particles in a substance or system.
• What are the two parts of internal energy often discussed?

  Potential energy stores and kinetic energy stores.
• Which type of energy is important for temperature changes?

  Kinetic energy
• How does heating a substance affect its internal energy?

  It transfers energy to the kinetic energy store of the particles, increasing their internal energy.
• What does temperature measure in a substance?

  The average internal energy of the substance.
• Why do some materials require more energy to increase their temperature than others?

  Because of their specific heat capacity.
• How much energy does water require to warm one kilogram by one degree Celsius?

  4,200 joules
• How much energy is needed to heat one kilogram of mercury by one degree Celsius?

  139 joules
• What is specific heat capacity?

  It is the amount of energy needed to raise the temperature of one kilogram of a substance by one degree Celsius.
• What happens when one kilogram of water cools by one degree Celsius?

  It releases 4,200 joules of energy to the surroundings.
• 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 for change in internal energy?


  It represents change.
• What does the symbol $\theta$ represent in the context of temperature?


  It represents temperature.
• How do you find the change in temperature using the energy transferred, mass, and specific heat capacity?

  Change in temperature = energy / (mass × specific heat capacity)
• What is the initial temperature of 800 grams of water in the example given?

  20 degrees Celsius
• How much energy is transferred to the water in the example?

  20 kilojoules
• What is the specific heat capacity of water used in the example?

  4,200 joules per kilogram per degree Celsius
• What is the final temperature of the water after the energy transfer in the example?

  25.95 degrees Celsius
• Why might the temperature not increase as much as calculated in real life?

  Because some energy would be lost to the surroundings as heat.
• What are the steps to calculate the final temperature of a substance when energy is transferred?

  1. Identify the mass of the substance.
  2. Determine the specific heat capacity.
  3. Calculate the change in temperature using the formula:

  $\Delta T =$$\frac{Q}{m \cdot c}$

  1. Add the change in temperature to the initial temperature to find the final temperature.
• What factors affect the temperature change of a substance when energy is added?

  • Mass of the substance
  • Specific heat capacity of the substance
  • Amount of energy transferred