1. Types of Chemical Reactions
5 types of reactions

2. Summary
Today you will perform experiments that include each of the major types of chemical reaction
These are
single replacement
double displacement
combination
decomposition
combustion

3. Single Replacement Ca + ZnSO4  Zn + CaSO4 Cl2 + 2NaBr  Br2 + 2NaCl
In this type of reaction an element in a compound is replaced by another
Ca + ZnSO4  Zn + CaSO4
Cl2 + 2NaBr  Br2 + 2NaCl

4. Double Replacement CaCl2 + ZnSO4  CaSO4 + ZnCl2
Two cations swap partners ….
CaCl2 + ZnSO4  CaSO4 + ZnCl2

5. Combination Reaction Ca + Cl2  CaCl2 CaO + H2O  Ca(OH)2
This happens when 2 substances become 1 substance
Or when 2 compounds make a larger compound
Ca + Cl2  CaCl2
CaO + H2O  Ca(OH)2

6. Decomposition Reaction
This is the opposite of a combination reaction it is when a substance falls apart into other substances
Ca(OH)2  CaO + H2O

7. Combustion Reaction CH4 + 2O2  CO2 + 2H2O
AKA burning, when a substance combines with oxygen
Often water and carbon dioxide are produced
CH4 + 2O2  CO2 + 2H2O

8. Evidence of a Chemical Reaction
Reactions in this experiment are conducted in water (solvent)
Here are indicators that a reaction has occurred
Formation of a Gas
A Precipitate Forms
Heat is Produced
A Color Change in Seen (unreliable)

9. Balancing Reactions Three Rules to Balancing Equations
Write correct Formulae of reactants and products
Use Stoichiometric coefficients in front of each compound so that the number of atoms of each type on the left hand side are the same as on the right
Use the smallest whole numbers possible as coefficients

10. The Reactions
1 mL (20 drops) 0.1 M CaCl2 + 1 mL (20 drops) 0.1 M Na3PO4
Heat 0.5 g of table sugar in a disposable test tube over a bunsen
what is the liquid forming on the side of the test tube?
3 mL H2O2 and a spatula tip of MnO2 and heat
a gas is evolved O2 – you can prove by adding a glowing splint
3 mL of 3 M HCl and a small piece of Zinc
after about 30 s bring a lighted splint to the mouth of the tube

11. The Reactions (continued)
1 mL 3M HCl + 1 mL 1.0 M Na2CO3
what is the gas? Place a lighted splint in the test tube
1 mL (20 drops) 0.1M CaCl2 in a test tube with 1 mL (20 drops) of 0.1M Na3PO4
Record your observations, does the solution go cloudy? If so a solid has formed and a reaction has taken place
1 mL (20 drops) 0.1 M FeCl3 and in a test tube 1 mL (20 drops) 0.1 M KSCN
Remember a color change indicates that a reaction has happened. Record your observations
2 mL (40 drops) 3M H2SO4 in a test tube, add 2 drops of Phenolphthalein from the bench, then 5 mL of 3M NaOH
Touch the bottom of the test tube, is the test tube warm? If so this is an exothermic reaction, pay attention to any color changes, phenolphthalein is colorless in acid and a hot fuscia pink in a base