Chemistry Basics

Gain a better understanding of chemistry by getting a handle on the basics: the laws, formulas, and reactions that make up some of the foundation of chemistry.

Acids and Bases

• An acid is an H+ donor, and a base is an H+ acceptor.

• pH = -log[H+]; [H+] = 10-pH

• pH = 7 is neutral; pH less than 7 is acidic; pH greater than 7 is basic.

Bonding

• In bonding, atoms lose, gain, or share electrons in order to have the same number of electrons as the nearest noble gas.

• Metal + nonmetal = ionic bond

• Nonmetal + nonmetal = covalent bond

• Electron filling pattern: 1s, 2s, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f

Gas Laws

Combined Gas Law: (P1V1)/T1 = (P2V2)/T2 (where T must be in kelvins)

Ideal Gas Law: PV = nRT (where R = 0.0821 l.atm/K.mol)

Isotope Representation

X = element symbol, Z= atomic number (# of protons), A= mass number (# of protons + # of neutrons)

Mole Concept

1 mole = 6.022 ∞ 1023 particles/mol = formula weight expressed in grams

Redox

Oxidation is loss of electrons; reduction is gain of electrons.

Solution Concentrations

weight/weight (w/w) % = (grams solute/grams solution) 100

molarity (M) = moles solute/liters solution

parts-per-million (ppm) = grams solute/1,000,000 grams solution = mg/l