1. Grab…. handouts on door. binders 1. Grab… handouts on door binders check your returned work folders  2. Begin the Do Now handout (10 min)

Parts of a Chemical Reaction Equation Physical Reaction Equations: MgSO4(s)  MgSO4(aq) H2O(s)  H2O(l) Chemical Reaction Equations: 2Na(s) + Cl2(g)  2NaCl(s) 2KClO3(s)  2KCl(s) + 3O2(g)

Parts of a Chemical Reaction Equation C3H8(aq) + O2(g) 3CO2(g) + 4 H2O(l) How many reactants are there and what are they? How many products are there and what are they? How many of each atom are there?

Counting Atoms in Compounds Step 1: Identify your elements in the compound Step 2: Distribute your subscripts Step 3: Distribute your coefficients a. 4PO4 b. 6C3H8O2 c. (CH4) 2N2

Counting Atoms Guided Practice How many atoms of each element are in the following molecules? 1. H2SO4 2. CaOH2 3. NaCl 4. (NH3)3PO4 5. 3H2O

1. 2 hydrogen, 1 sulfur, 4 oxygen 2. 1 calcium, 1 oxygen, 2 hydrogen Answers 1. 2 hydrogen, 1 sulfur, 4 oxygen 2. 1 calcium, 1 oxygen, 2 hydrogen 3. 1 sodium, 1 chlorine 4. 3 nitrogen, 9 hydrogen, 1 phosphorus, 4 oxygen 5. 6 hydrogen, 3 oxygen

Types of Reactions Stations 1) Determine which of the 5 types of chemical reactions is shown for each HCl + Mg à MgCl + H2 NaHCO3 + CH4CO2  CO2 (g) + H2O (l) + C2H3O2Na Pb(NO3)2 (aq) + KCl (aq)  KNO3 (aq) + PbCl2 (s) 2) Make an atom inventory of the reactants and products for each reaction

Parts of a Chemical Reaction Equation C3H8(aq) + O2(g) 3CO2(g) + 4 H2O(l)

Key Point #1 Key Point #1: Law of Conservation of Mass = Mass is not lost or gained in a chemical reaction “What you put in is what you get out”

Key Point #2 Key Point #2: Balancing Reactions ensures the law (of conservation of mass) is obeyed Steps to Balancing Reactions: 1. Make an atom inventory of reactants and products 2. Alter coefficients to balance atoms 3. Balance your HO’s last!

Balancing Reactions Puzzle 20 min to determine how to balance reactions! - If finished with all practice, check your answers on the answer key up front!

Parts of a Chemical Reaction Equation C3H8(aq) + O2(g) 3CO2(g) + 4 H2O(l)

Types of Reactions Stations 1) Now try balancing the following equations: HCl + Mg à MgCl + H2 NaHCO3 + CH4CO2  CO2 (g) + H2O (l) + C2H3O2Na Pb(NO3)2 (aq) + KCl (aq)  KNO3 (aq) + PbCl2 (s)

Practice makes Perfect! Using work sheet from the beginning of last week (check your resources section)… - Balance each of the reactions shown on the hand out

Recap of Today… What are the 5 types of chemical reactions? What is the Law of Conservation of Mass?