1st of thermodynamics

• How do external forces affect the state of a system in both Newton's first law and the first law of thermodynamics?

  They change the state of motion or energy
• In the context of the shopping bags, what does the application of brakes demonstrate about energy transfer?

  It shows energy transfer due to external work
• What happens to the motion of unsecured shopping bags when brakes are applied in a moving car?

  They decelerate due to external force
• What are the key principles of Newton's first law and the first law of thermodynamics?

  • Newton's first law: momentum conserved unless acted upon
  • First law of thermodynamics: energy conserved unless heat/work occurs
• What are the signs of heat transfer and internal energy change in an exothermic reaction?

  $Q < 0, ΔU < 0$
• How does Newton's first law of motion compare to the first law of thermodynamics?

  Newton's law conserves momentum; thermodynamics conserves energy
• What does the first law of thermodynamics state about energy in a closed system?

  Energy remains constant unless external work or heat occurs
• What is the difference between exothermic and endothermic reactions in terms of heat transfer?


  Exothermic releases heat; endothermic absorbs heat.
• What does Newton's first law illustrate about motion?

  It illustrates conservation of motion
• How does the example of unsecured shopping bags in a moving car relate to Newton's first law?

  They continue moving until a force acts
• What is the sign of heat transfer (Q) in an endothermic reaction?


  Q is positive
• What are the signs of heat transfer and internal energy change in an endothermic reaction?

  $Q > 0, ΔU > 0$
• How does the first law of thermodynamics apply to endothermic reactions?

  • Heat is absorbed from surroundings
  • Internal energy increases
  • Q > 0 and ΔU > 0