Compounds Are Made up of Atoms of More Than Just One Element

Chapter 2

Elements are made up of small particles called atoms. All atoms of the same elements are identical.

Compounds are made up of atoms of more than just one element.

Chemical reactions are the separation, combination or rearrangement of atoms, it doesn’t result in their creation or destruction.

Atoms are composed of electrons (negatively charged), neutrons (neutrally charge), and protons (positively charged).

Z is the Atomic Number is the number of protons in the nucleus of each atom.

A is the Mass number is the total number of neutrons and protons present in the nucleus of an atom of an element.

The periodic table is a chart where elements are organized depending on how similar they are. The horizontal rows are called periods and the vertical columns are called groups or families.

The periodic table can be classified into metals, nonmetals, and metalloids.

A molecule is two or more atoms in an arrangement created by chemical forces.

An ion is an atom or a group of atoms that has either a positive or negative charge.

Chemical formulas shows the exact number of atoms of each element in the smallest unit of a substance.

Nomenclature

To name Ionic Compounds (compounds made of of cations and anions):

Add the suffix -ide to the anions.

For example, O2- is named Oxide

Al2O3 therefore is Aluminum Oxide

To name Transition Metals, you say the name of the metal and the number of ions.

For example, F2+ is named Iron (II)

FeCl2 therefore is Iron (II) Chloride.

Naming other molecular compounds can consist of

Adding prefix

Naming Acids and Bases

Acids start with a hydro- prefix and an –ic ending, for example HCl is named hydrocloric acid.

Chapter 3

Atomic mass is the mass of the atomic in amu (atomic mass units). Moles are the amount of a substance that contains as many elementary entities as there are atoms in exactly 12 g of the carbon-12 isotope.

 Grams = number of atoms divided by Avogadro’s number.

Number of atoms = grams divided by

Avogradro’s number

Avogadro's number = 6.0221415 × 1023

Percent composition of an element = n x molar mass of element divided by molar mass of compound

For example to get the percent composition for iron(III) oxide you would write

Chemical Equations uses chemical symbols to describe a chemical reaction.

Reactants are starting materials and products are the finishing results.

Balancing chemical equations

Great tutorial on balancing chemical equations

Amounts of Reactants and Products

to find the number of moles in 2.00 g of NaCl, one would do the following:

For example to completely react with 85.0 grams of iron (III) oxide, 28.7 grams of aluminum are needed.

Chapter 4

General Properties of Aqueous Solutions

Solute is the substance present in a smaller amount and a solvent is the substance present in a larger amount.

An electrolyte is a substance that results in a product that can conduct electricity, when dissolved with water.

Acids

• Have sour taste
• Cause color changes in plant dyes
• React with metals to produce hydrogen gas.
• React with carbonates and bicarbonates to produce carbon dioxide gas.
• Aqueous acid solutions conduct electricity.

Bases

• Have bitter taste
• Feel slippery
• Cause color changes in plant dyes
• Aqueous base solutions conduct electricity.

Oxidation Reduction Reactions are electron-transfer reactions.

For example,

Reduction reaction is a half=reaction that involves the gain of electrons. The reducing agent donates electrons, whereas the oxidizing agent accepts electrons.

There is 3 types of Redox reactions:

Combination reaction is when two or more substances combine to form a single product.

Decomposition reaction where is the opposite, in where there’s breakdown of a compound into two or more components.

Displacement Reactions occur when an ion in a compound is replaced by an ion of another element.

• Hydrogen displacement
• Metal displacement
• Halogen displacement

Molarity is calculated as following:

Titration is when a solution of accurately known concentration is added gradually to another solution of unknown concentration, until the chemical reaction between the two solutions is complete.