Writing Chemical Formulas

Study Notes

A chemical equation is a representation of a chemical reaction using chemical formulas and symbols
Components of a chemical equation:
- Reactants (left side)
- Products (right side)
- Arrow (→) indicating the direction of the reaction
- Coefficients (numbers in front of formulas) indicating the mole ratio of reactants and products
Types of chemical equations:
- Synthesis (combination) reaction: A + B → AB
- Decomposition reaction: AB → A + B
- Replacement reaction: A + BC → AC + B
- Combustion reaction: fuel + O2 → products

Oxidation number (also known as oxidation state) is a number assigned to an element in a compound
Indicates the number of electrons gained or lost by an element in a reaction
Rules for assigning oxidation numbers:
- Free elements (not in a compound) have an oxidation number of 0
- Monatomic ions have an oxidation number equal to their charge
- In a compound, the oxidation number of the more electronegative element is negative
- The sum of oxidation numbers in a neutral compound is 0

Reactants: substances that are consumed or changed during a chemical reaction
Products: substances that are formed or produced during a chemical reaction
Characteristics of reactants and products:
- Reactants are typically written on the left side of the equation
- Products are typically written on the right side of the equation
- Reactants are consumed or changed during the reaction, while products are formed or produced
- The amount of reactants and products can be adjusted using coefficients to balance the equation

Chemical formulas represent the composition of a molecule using symbols of elements and numbers indicating the ratio of atoms.
Elements are written in the order of metals (left to right), nonmetals (left to right), and then hydrogen (right).
Polyatomic ions are treated as a single unit in chemical formulas.

Chemical equations represent chemical reactions using chemical formulas and symbols.
Components of a chemical equation include reactants, products, an arrow indicating the direction of the reaction, and coefficients indicating the mole ratio.
There are four types of chemical equations: synthesis (combination), decomposition, replacement, and combustion reactions.

Oxidation numbers indicate the number of electrons gained or lost by an element in a reaction.
Free elements have an oxidation number of 0, while monatomic ions have an oxidation number equal to their charge.
In a compound, the oxidation number of the more electronegative element is negative, and the sum of oxidation numbers in a neutral compound is 0.

Reactants are substances consumed or changed during a chemical reaction, while products are substances formed or produced during a reaction.
Reactants are written on the left side of the equation, while products are written on the right side.
The amount of reactants and products can be adjusted using coefficients to balance the equation.
Reactants are consumed or changed during the reaction, while products are formed or produced.