Matter and Energy Lecture Notes

Key Properties of Matter

• Matter
  • Has mass
  • Takes up space
  • Common forms include solid, liquid, and gas
• Energy
  • Capacity to do work
  • Has no mass
  • Takes up no space
  • Exists in forms such as heat, light, sound, motion, and electricity

Law of Conservation of Matter

• Matter is neither created nor destroyed
• The mass of matter remains constant during physical or chemical reactions
• Amount of matter remains the same before and after a process
• Changes in form (e.g., solid to gas) can make matter appear to disappear

Physical and Chemical Reactions

• Chemical Reaction: Two substances react to create a new substance
• Physical Reaction: No new substance is created; involves changes of form (solid to liquid to gas)

Experiment: Ice to Water to Steam

• Ice cubes in a pan, weigh one pound
• Ice melts to water, weight remains the same
• Water boils into steam, weight remains the same if steam is collected
• Demonstrates matter's conservation through physical state changes

Chemical Reaction: Burning Wood

• Wood burning results in ash, water (H2O), and carbon dioxide (CO2)
• Ash weighs less than the original wood due to gases released
• Combustion involves reacting with oxygen, forming water and carbon dioxide
• Gases from burning go up the chimney
• CO2 contributes to global warming
• Chemical equation: Wood + Oxygen → Ash + Water + CO2

Controlled Demonstration of Conservation of Matter

• Use a sealed glass container with wood and oxygen
• Heat externally to burn wood inside
• Observe formation of ash, water mist, and carbon dioxide
• Weighing before and after shows total mass remains constant
• CO2 is invisible but measurable post-reaction

Conclusion

• Demonstrates and confirms the law of conservation of matter
• Starting and ending component weights are identical