Chemistry Unit 4: Reactions and Stoichiometry

Throughout our unit 4 in Chemistry, we learned about reactions and stoichiometry. In this unit we went over, types of reaction, did some labs and did a few calculation on the reaction rate.

There are five types of reaction: 

  1. Synthesis – Two substances react to form a single product.
    1. x+y → xy
  2. Decomposition – A single reactant decomposes or breaks down into two or more products
    1. A    →    B + C
  3. Combustion – One reactant (fuel) combines with oxygen to produce an oxide and water.
    1. Fuel + O2  →    oxide + H2O
  4. Single Replacement – One, more reactive element, replaces another.
    1. M  + AX  →MX + A
  5. Double Replacement – A reaction in which the cations and anions of both reactants switch partners.
    1. AX  + DZ    →    AZ + DX

Those are the five types of reaction that can happen to the molecule when they are reacting.  We also went over the reaction rate. A few words that I want to tell are activation energy, activated complex, reactant, and product. 

Activation energy (Ea)  is the minimum amount of energy to start a reaction.

Activated complex is a reaction progresses from reactants to products, it goes through a transition state.

The reactant is a substance in reaction before becoming the product.

A product is as the reaction occurs products is produced.

Reactants → Products
  • Start with a concentration of reactants (reagents)  which decrease over time.
  • The reaction occurs quickly at the beginning and then slows down.

There are four(4) major factors in looking at the effect in the reaction rate:

  1. Concentration-  As the concentration of reactants increases, there are more particles, so more collisions, and the rate will increase.
  2. Temperature As temperature increases, the particles move faster, so more collisions occur, and the rate increases.
  3. Surface Area- Reactions take place on the surface of the solid, so as of surface area increase, reaction rate increases. *Notice they are a direct relationship
  4. Catalyst- a substance that speeds up a reaction without being consumed

Through this unit, I had understood the difference between reaction rate and reaction time. As well as understanding deeper into looking at the reaction progress of the molecule. This lesson really interests me as a student who doesn’t really interest in Chemistry and I think it is really fun to learn something like this topic. 

Leave a Reply

Your email address will not be published. Required fields are marked *