temperature changes and energy

• What are the three states of matter in everyday life?

  Solids, liquids, and gases
• What causes the differences between the three states of matter?

  The arrangement, spacing, and motion of the particles
• What are the characteristics of particles in a solid?

  • Regular arrangement
  • Vibrate about a fixed position
  • Sit very closely together
• What are the characteristics of particles in a liquid?

  • Randomly arranged
  • Move around each other
  • Sit close together
• What are the characteristics of particles in a gas?

  • Randomly arranged
  • Move quickly in all directions
  • Are far apart
• How can adding or removing energy from a material change its state?

  It can cause the material to melt, boil, or condense
• What is the process called when a solid turns directly into a gas?

  Sublimation
• What happens when a gas is cooled?

  It condenses into a liquid
• What is the difference between boiling and evaporation?

  Boiling is an active process, while evaporation is passive
• What remains constant during changes in state?

  The number of particles and the total mass
• Why are changes in state called physical changes?

  Because they can be reversed
• What happens to chemical bonds when a material is heated or cooled?

  They may form, break, or stretch
• What is internal energy?

  The total amount of kinetic and chemical potential energy of all particles in a system
• How does heating a material affect its particles?

  Particles gain speed and kinetic energy
• What does the conservation of energy state regarding energy transferred to a material?

  It will be distributed between the chemical and thermal stores of internal energy
• What is the specific heat capacity of water?

  4,200 J/kg°C
• What is the formula for calculating thermal energy changes?

  \[

  \Delta E_t = m \times c \times \Delta \theta

  \]

  Where:

  • \(\Delta E_t\) is change in thermal energy (J)
  • \(m\) is mass (kg)
  • \(c\) is specific heat capacity (J/kg°C)
  • \(\Delta \theta\) is temperature change (°C)
• How much energy is needed to raise the temperature of 3 kg of copper by 10°C if its specific heat capacity is 385 J/kg°C?

  $change \, in \, thermal \, energy =$$3 \, kg \times 385 \, J/kg°C \times 10°C =$$11,550 \, J$
• What is specific latent heat?

  The amount of energy required to change the state of 1 kg of a material without changing its temperature
• What are the two types of specific latent heat?

  • Latent heat of fusion: energy needed to melt or freeze a material
  • Latent heat of vaporisation: energy needed to boil or condense a material
• What is the specific latent heat of fusion for water?

  334 kJ/kg
• What is the specific latent heat of vaporisation for water?

  2,260 kJ/kg
• How much energy is needed to change 1 kg of ice into 1 kg of water?

  334,000 J
• How can latent heat be measured from a heating or cooling curve?

  • Monitor temperature changes over time
  • Identify horizontal lines where energy is used to change state
  • The length of the horizontal line indicates the amount of energy used
• If a heater provides 60 W of power for 1 hour and 3 minutes, how much energy is supplied?

  3,780 J
• If 100 g of water absorbs 226,800 J, what is the latent heat of vaporisation for 1 kg of water?

  2,268,000 J/kg
• What happens when 1 kg of water at 75°C is heated with 2.5 MJ?

  1. Energy raises temperature to 100°C
  2. Remaining energy turns boiling water into steam
  3. Final energy raises temperature of steam
• What is the final temperature of steam if it started at 100°C and heats up by 72.6°C?

  172.6°C