Chemical Reactions, Equations

back to Chemistry $$\require{mhchem}$$

describe a reaction

video: Salman Khan: Chemical Reactions Introduction

using two examples

• combine molecular hydrogen and oxygen into energy and water (oxidation-reduction)
• combine bicarbonate anion and a hydrogen cation into carbonic acid (reversible)

reduction

oxidation-reduction

hydrolysis

$$\require{mhchem}$$

reactants $->$ products

reagents $->$ products

video: Salman Khan: Balancing Chemical Equations

using example of combining aluminum and oxygen (dioxygen) to form aluminum oxide

finding the quantity of each molecule on both sides of the equation.

The initial equation identifies the molecules and the reaction. Theoretical

Balancing shows the quantity of each molecule in the reaction. Actual

1. the molecules involved

2. the quantity of each molecule

3. the change in charge of each molecule

4. the energy exchange (thermodynamics)

video: Salman Khan: Molecular, complete iconic, and net iconic equations

Showing ionic charge explicitly in an equation.

Sodium chloride plus silver nitrate → ? plus silver chloride

Molecular equation: $$\ce{NaCl(aq) + AgNO3(aq) -> NaNO3(aq) + AgCl(s)}$$

Complete ionic equation: $$\ce{Na+(aq) + Cl^{-}(aq) + Ag+(aq) + NO3^{-}(aq) -> Na+NO3^{-}(aq) + AgCl(s)}$$

Net ionic equation: $$\ce{Cl^{-}(aq) + Ag+(aq) -> AgCl(s)}$$

spectator ion

“Water is a polar molecule. That's what makes it such a good solvent.”

wants an electron, halogens

has an extra electron to give away, alkali metals

sodium chloride NaCl

sodium iodide NaI

potassium chloride KCl

lithium chloride LiCl