Ch. 11

• What do chemical equations represent? How do they do this?

  They represent the reactants and products in a chemical reactionl using symbols and formulas
• What are the rquirements for all chemical equations/reactions?

  Must show all reactants and products Formulas must be correct Law of conservation of mass must be satisifed (has to be balanced)
• What are examples of phases in chemical reactions?

  Gas, liquid, solid, or aqueous
• What are the symbols of the possible phases for chemical reactions?


  Gas: (g) or ↑, liquid: (l), solid: (s), aqueous (aq)
• What does aqueous mean?

  Dissolved in water
• One way reaction symbol ->
• Reversible reaction symbol <->
• Heat added to reaction symbol

  ∆ (place over arrow for reaction) ->
• What is a catalyst?

  A substance that speeds up a reaction without being used up in the reaction
• Catalyst symbol in a chemical reaction

  cat (place over arrow) -->
• What phase of matter is a precipitate and what side of the reaction is it on?

  Only a solid, only on the products side
• Precipitate symbol in a chemical reaction


  (ppt.) or ↓ (or (s), but it is very general)
• In a chemical equation, which of the following have to be equal, and which don't: atoms, grams (mass), and moles

  Atoms and grams have to be equal (sides must add up to eachother), while moles don't
• What are the 5 types of chemical reactions?

  Synthesis, decomposition, combustion, single replacement, and double replacement
• What is a synthesis reaction?

  A direct combination where the energy needed to make the reaction happen is endothermic (energy absorbed, the products have higher energy)
• Find the right products, then you balance
• What is a general example of a synthesis reaction?

  A (element) + B (element) -> AB (compound)
• What is a more specific example of a synthesis reaction using magnesium and chlorine?

  Mg + Cl2 -> MgCl2
• What is a decomposition (analysis) reaction?

  A reaction that needs energy to happen, usually in the form of heat or electricity
• What is a general example of a decomposition reaction?

  AB (compound) -> A (element) + B (element)
• When there is a hydrate in the reactants, what goes on top of the arrow?

  delta symbol - ∆ (for heat)
• What is an example of a more specific decomposition reaction with mecury and oxygen?

  2HgO -> 2Hg + O2
• When on the reactants side of the equation (not really always the reactant side, but the __ + __ side), what is always the subscript of a diatomic element?

  _2
• What is a combustion chemical reaction?

  The reaction of hydrocarbons and oxygen to yield carbon dioxide and water. They release energy, so they are exothermic (they have less energy in the products)
• If you see CHO in the reactants of an equation, what does that mean?

  It means that the reaction is a combustion reaction, and therefore the products will be CO2 and water
• What is the general example of a combustion chemical reaction?

  CxHy + O2 -> CO2 + H2O
• What is methane?

  CH4
• What is propane?

  C3H8
• What is butane?

  C4H10
• What is ethyl alcohol?

  C2H5OH
• What is an example of the combustion (chemical reaction) of methane (CH4)?

  CH4 + 2O2 -> CO2 + 2H2O
• What is a single replacement chemical reaction?

  Reactions that take place in aqueous solutions and need very little energy
• What are the types of single replacement reactions?


  A: positive ions switch, B: negative ions switch
• What is the general example of a single replacement reaction (where positive ions switch)?

  AB (compound) + M (element/metal) -> MB (compound) + A (element)
• What is an example of a single replacement reaction where positive ions switch, between magnesium, hydrogen, and iodine?

  2HI(aq) + Mg(aq) -> MgI2(aq) + H2
• What is the general formula of a single replacement reaction where negativ ions switch?

  AB (compound) + X (element/nonmetal) -> AX (compound) + B (element)
• What is an example of a single replacement reaction where negative ions switch between sodium chloride and diflouride?

  2NaCl + F2 -> 2NaF + Cl2
• What is a double replacement chemical reaction?


  A reaction that takes place in aqueous solutions with little energy needed, and usually forms one soluble ionic product (aka aqueous) and either a precipitate, water, or a gas that bubbles out of the water
• If you see H2O when dealing with a type of chemical reaction, what should you do?

  Change it to HOH because it's less confusing
• What is the general formula for a double replacement reaction?

  AB (compound) + CD (compound) -> AD (compound) + CB (compound)