States of Matter and Changing State

• What are the three states of matter?

  Solid, liquid, gas
• What does the particle theory state about solids?

  • Regular arrangement
  • Fixed position
  • Very close together
• What does the particle theory state about liquids?

  • Random arrangement
  • Move around each other
  • Close together
• What does the particle theory state about gases?

  • Random arrangement
  • Move quickly in all directions
  • Far apart
• What happens to a substance during melting and boiling?

  The substance gains energy
• What happens to a substance during condensing and freezing?

  The substance loses energy
• What is the boiling point?

  The temperature at which a substance boils
• What is the melting point?

  The temperature at which a substance melts
• What is a balanced equation?

  • Same number of atoms of each element
  • Equal on both sides of the equation
  • Example: 2Mg + O₂ → 2MgO
• How many magnesium atoms are in the equation 2Mg + O₂ → 2MgO?


  2 magnesium atoms
• How many oxygen atoms are in the equation 2Mg + O₂ → 2MgO?


  2 oxygen atoms
• What does the conservation of mass state?

  No atoms are created or destroyed
• What happens to the total mass of reactants and products in a chemical reaction?

  They are equal
• What would happen if you weigh an unsealed container before and after a reaction?

  There will be a change in mass
• What causes a decrease in mass during a reaction?

  • A gas is made
  • Gas is lost and escapes
  • Mass is no longer constant
• How is the amount of energy needed to change state related to particle forces?

  Stronger forces mean higher melting and boiling points
• What are the state symbols for solid, liquid, gas, and aqueous?

  • Solid: (s)
  • Liquid: (l)
  • Gas: (g)
  • Aqueous: (aq)
• What is the state symbol for gas?

  (g)
• What is the state symbol for liquid?

  (l)
• What is the state symbol for solid?

  (s)
• What is the state symbol for aqueous?

  (aq)
• What is the chemical formula for carbon dioxide?

  CO₂