Unit 4 - Chemical Reactions

Mr. Germanoski's AP Chemistry class

RedOx Reactions

Reactions where electrons have been transferred from one chemical species to another. most common type

Precipitation Reactions

Double ionic replacement reactions where a solid forms from aqueous solutions.

Acid-Base Reactions

Transfer of one or more protons between chemical species.

Which ions are always soluble in water?

SNAP - Sodium (Na⁺), Nitrate (NO₃^-), Ammonium (NH₄⁺), and Potassium (K⁺)

LEO

Lose Electrons Oxidation

GER

Gain Electrons Reduction

Oxidation Number for Group 1, Group 2, and Group 17?

Same as their ionic charge

Oxidation Number for Oxygen? 

-2 (Except H₂O₂ which is -1)

Oxidation Number for Hydrogen?

+1

Acid-Base Reactions

Acids donate protons (H⁺)

Bases accept protons (H⁺)

Conjugate Acid

When a base gains a proton

Conjugate Base

When an acid loses a proton

Physical Change

Physical property of a substance changes without changing the composition.

Chemical Change

Property of a substance changes - breaking of bonds and formation of new bonds

What at the end of a compound makes it soluble?

Nitrates (ending with NO₃^-) and acetates (ending with C₂H₃O₂^-₎

What is it at the start of a compound that makes it soluble?

Alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺), ammonium ion (NH₄⁺)

What happens to soluble compounds in a water solution?

Exists as separate ions

What happens to insoluble compounds in a water solution?

Exists as complete compounds

Ionic Bonding

High melting and boiling points

Average form of Precipitation Reactions

AB (aq) + CD  (aq)——> AD (s) + CB (aq)

Average form of acid-base reactions

Acid + Base ——> Salt + Water

Average form of redox reactions

A+B →AB , AB →A+B, A+BC→AC+B

How to identify a salt?

Look for cations and anions

Nitrate

NO₃^-

Nitrite

NO₂^-

Sulfate

SO₄^2-

Sulfite

SO₃^2-

Group one charge

+1

Group two charge

+2

Group three charge

+3

Group fifteen charge

-3

Group sixteen charge

-2

Ggroup 17 charge

-1

How to tell if it’s a chemical change?

• Color

• Heat

• Formation of a gas

• Production of light

• Precipitate or any new substance forms

• Any change in chemical properties

Ammonium

NH₄⁺

Single Replacement Reactions

A + BC →AC+B

Spectator Ions

Remain unchanged on both sides of an equation.

Brønsted-Lowry theory

defines an acid as a proton donor and a base as a proton acceptor