Lab 5: Types of Reactions
Objectives:
1. Observe changes in chemical and physical properties during a variety of chemical
reactions
2. Write balanced chemical equations for all reactions carried out
3. Identify type of reaction carried out (some may be more than one type)
Background:
A chemical reaction consists of reactants and products. The reactants are what you
start with (also called starting materials) and the products are the new compounds that form
during the reaction. There are several reaction types discussed in your text including. All
reactions can be described as redox or non-redox reactions. The former involves changes in
oxidation number (exchange of electrons) while the latter does not. From there we can
further categorize the types of reaction. Redox reactions can be classified as combination,
decomposition or single replacement. Non-redox reactions can be classified as combination,
decomposition or double replacement.
Combination: A + B  AB
Decomposition: AB  A + B
Single-displacement: A + BC  AC + B
Double-displacement: AB + CD  AD + CB
In addition, reactions can be classified as exothermic (releasing heat) or endothermic
(consuming heat). In this lab you will carry out various reactions and make careful
observations about what you see. In the data report you will express them as balanced
chemical equations and determine what type of reaction has taken place.
Pre-Lab: (To be submitted at the beginning of lab)
1. Summary of the procedure in your own words.
2. What type of reaction do you expect each to be?
3. Compare reaction 7 to reaction 8. Are they the same reaction in different directions?
How can you tell?
Safety Notes:
 Wear your safety goggles at all times
 Handle all chemicals carefully (rinse them off your skin immediately)
 Take only the amount of chemicals that you need and never put unused chemicals
back into the reagent bottle
 Discard all used or leftover chemicals in the waste containers provided (do not pour
any chemicals down the sink and do not put your rinse water in the waste)
 Clean up any spills immediately and clean up everything when finished
Edited by Nick Buker 2/10/10
1
Procedures:
Carry out the following reactions. For each reaction, carefully write down all
observations (color change, gas evolution, formation of a precipitate, or temperature
change) below the appropriate reaction on the pages you created for the pre-lab. Your
observations will be turned in and graded along with the data sheet.
Use clean test tubes for the reactions.
Reaction #1
Mg + O2  MgO
Procedure: Clean a Mg (magnesium) strip with glass or steel wool. Using tongs to hold the
Mg strip, burn the strip. Dispose the product in the solid waste container.
Reaction #2
NH4OH(aq)  NH3(g) + H2O
Procedure: Open the bottle of conc. NH4OH (ammonium hydroxide). Test the pH of the
vapors just above the mouth of the bottle using a moistened piece of pH paper. Do not put
the paper in the bottle or let it touch the mouth of the bottle. When finished close the bottle
of conc. NH4OH.
Reaction #3
Mg (s) +
HCl (aq)  H2
(gas)
+
Mg2+(aq) + Cl-(aq) .
Procedure: Place a strip of Mg in 1 mL of 0.1M HCl (hydrochloric acid).
Reaction #4

AgNO3(aq) + HCl (aq)
AgCl(s) +
HNO3 (aq)
Procedure: Mix 0.1M HCl with 0.1M AgNO3 (silver nitrate) in equal volumes.
Reaction #5 HCl(aq) + NaOH(aq)  H2O + NaCl(aq)
Procedure: Measure the pH of 0.1M HCl and 0.1M NaOH (sodium hydroxide). Mix the two
in equal volume and stir well. Watch for any changes in temperature. Measure the pH of
this mixture. Did the reaction generate heat?
Reaction #6 CO32- (aq) + H+ (aq) 
H2CO3 (aq)  H2O (l) + CO2 (g)
Procedure: Place a small scoop of CaCO3 (s) (calcium carbonate) in 2 mL of 0.1M HCl.
Reaction #7 Cu (s) +
ZnSO4(aq)  CuSO4(aq)
+
Zn (s)
Procedure: Place a small piece of Cu (s) (copper) in 1 mL of 0.1 M ZnSO4 (zinc sulfate).
Reaction #8 Zn (s) + CuSO4(aq)

Cu (s) +
ZnSO4(aq)
Procedure: Place a small piece of Zn (s) (zinc) in 1 mL of 0.1M CuSO4 (copper sulfate).
Edited by Nick Buker 2/10/10
2
Data Sheet (To be attached to your lab report. Recopy if messy): For each reaction write the
balanced chemical equation. List all types of reaction that apply: Combination, Decomposition,
Replacement (single/double), Combustion and Redox. Record any observations such as formation of
heat, generation of bubbles or precipitation of a solid etc.
Reaction 1: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 2: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 3: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 4: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 5: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 6: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 7: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Reaction 8: Balanced chemical equation:
Type (or types) of reaction:
Obserations:
Edited by Nick Buker 2/10/10
3
Lab Report Guide:
- 1. Results (5 pts)
o Data sheet neatly filled out with balanced equations, correctly identified types of
reaction and detailed observations
- 2. Post Lab Questions (5 pts)
o Typed answers to the Post Lab questions. Note that single sentence answers
will not suffice. State the answer to the question followed by a brief
description of the evidence supporting that answer.
Post Lab Questions: (Typed answers to be submitted with lab report)
1. In reaction #4, what was the solid that formed in the reaction? In reaction #3, what
gas caused the bubbling in the solution?
2. Did the reaction types match your predictions?
3. The law of conservation of mass states that the mass of the reactants should be
exactly equal to the mass of the products. When a piece of firewood burns the mass
of the ashes is much lower than the mass of the wood. Where did the remaining
mass go?
4. Where you surprised by the results of reactions 7 and 8? Why do these results make
sense? Hint reactions generally proceed from high energy to low energy like a
boulder freely rolling down a hill.
5. When iron or steel nails rust, their mass increases. Does this break the law of
conservation of mass?
Edited by Nick Buker 2/10/10
4