Lab: Types of Chemical Reactions

TYPES of CHEMICAL REACTIONS

In this lab we performed various chemical reactions in the lab. We recorded our observations and identified the type of reaction that took place, eventually writing a balanced chemical equation. The purpose of this lab was to become more familiar with the five types of chemical reactions: synthesis, decomposition, single-displacement, double-displacement, and combustion.

Introduction/Background:

Here are some descriptions of the different types of reactions:

Synthesis - when there is a combination of 2 or more substances and a compound results; A+B->AB.

Decomposition - opposite of synthesis. when a compound is broken down into simpler substances, usually through electrolysis; AB -> A + B

Single-Displacement - A metal replaces a metal, or a nonmetal replaces a nonmetal; A + BC -> AC + B

Double-Displacement - A metal replaces a metal, and a nonmetal replaces a nonmetal; AB + XY -> AY + XB Combustion - when all substances in a compound are combined with oxygen which then produces carbon dioxide (CO2) and water (H2O).

Combustion is commonly called burning because it is an exothermic reaction (heat is produced); CxHy + O2 -> CO2 + H2O

MATERIALS:

• Safety Gear (goggles and apron)
• 3 test tubes
• test tube rack
• Bunsen burner
• copper sulfate (CuSO4)
• Zinc Metal (Zn)
• Barium Nitrate (Ba(NO3)2)
• Hydrochloric Acid (HCl)
• Hydrogen Peroxide (H2O2)
• Magnesium Oxide (MnO2)
• Splints

PROCEDURE: Obtain 3 small test tubes after putting safety gear on.

1. In the 1st test tube, place a piece of zinc and about 1/2 mL of CuSO4 solution. Record observations.
2. In the 2nd test tube, add about 1/2 mL Ba(NO3)2 solution to about 1/2 mL of CuSO4 solution. Record observations.
3. In the 3rd test tube, place a piece of magnesium ribbon. Add about 1/2 mL of HCl solution. Record observations.
4. Light a bunsen burner (burning propane gas, C3H8). Record observations of the flame.
5. Rinse out the first test tube. Add about 2 mL H2O2 solution. Lightly heat it. Record observations.
6. Add a pinch of MnO2 (catalyst) to the H2O2 solution. Lightly heat it. Record observations.

DATA / ANALYSIS

In performing these chemical reactions, we have learned of the possible types and different products that can result from the many combinations of solutions. For instance, there are many different combinations that a solid(s), gas(g), or liquid(aq) can result in the other.


BALANCED EQUATIONS

1. Zn + CuSO4 --> ZnSO4 + Cu Single-Displacement Reaction

2. Ba(NO3)2 + CuSO4 --> BaSO4 + Cu(NO3)2 Double-Displacement Reaction

3. Mg + 2HCl --> MgCl2 + H2 Single-Displacement Reaction

4. C3H8 + 5O2 --> 3CO2 + 4H2O Combustion Reaction

5. 2H2O2 --> 2H2O + O2 Decomposition Reaction





Observations/ Conclusions:

• Some form of noticeable change occurred in each of the reactions (dur du dur)
• In reactions releasing oxygen or hydrogen (bubbles) created a reaction from the lit splint (relighting of flame or spark/pop)
• Zinc has a higher reactivity than copper
• In the Barium Nitrate + Copper Sulfate Reaction, there was a distinct change in color and the powder that formed sunk to the bottom (picture to the right)