Saturday, January 29, 2011

Balancing Equations and Types of Reactions

We balance the number of atoms in the reactant side and the product side to make them equal, but how do we do it?
A beginner's guide to balancing equations by Mr. Anderson!
Watch this as a review for balancing equations from Grade 10 Science.

Types of Reactions
- There are six types of reactions : Synthesis, decomposition, single replacement, double replacement, combustion and neutralization. For now, we will cover the first 3 types of reactions first.

- combines 2 or more reactants to make one product    (A+B ---> C)

eg. 4 Fe + 3 O2 → 2 Fe2O3 
eg. CO2 + H2OH2CO3

Decomposition- One reactant is broken into 2 or more products (A---> B+C)

eg. 2KClO3 → 2KCl + 3O2
eg. 2H2O2 → 2H2O + O2

Single Replacement.
- an element replaces an ion in an ionic compound
- non-mental elements will replace a negative ion
- mental elements will replace a positive charged ion

eg. Cl2 + 2NaBr → 2NaCl + Br2
eg. Zn + 2HCl → ZnCl2 + H2

Activity Series

- Not all replacement reactions are possible
- This is because some elements are more reactive than another due to the amount of electrons in the outer shell
- If the element that is doing being replaced is lower down in the chart than the one doing the replacing, the replacement is POSSIBLE. Otherwise, the reaction is not possible, meaning that no reaction will occur.

eg. Fe  + CuSO4  → Cu  + FeSO4
This reaction is possible because iron is higher up on the chart so it's able to knock copper out

eg. I2 + 2KBr → no reaction
There will be no reaction because Iodine is not as reactive as Bromide

- Catherine

No comments:

Post a Comment