ACIDS, BASES, SALTS and H Scale p

Four types of Chemical Equations Synthesis two or more elements or compounds may combine to form a more complex compound. Basic form: A  +  X  →    AX EX. 2Mg(s)  +  O2(g)  →    2MgO(s) Decomposition A single compound breaks down into its component parts or simpler compounds. Basic form: AX  →   A  +  X Ex. CaCO3(s)  →    CaO(s)  +  CO2(g)

Four types of Chemical Equations Single Replacement: a more active element takes the place of another element in a compound and sets the less active one free Basic form: A  +  BX  →    AX  +  B   EX. Fe(s)  +  CuSO4(aq)  →    FeSO4(aq)  +  Cu(s) Double Replacement: parts of two compounds switch places to form two new compounds. Two reactants yield two new products EX. AB + XY ---> AY + XB EX. NaCl + H2SO4 ---> Na2SO4 + HCl

Acids HCl or H2SO4 H+1 + H2O  H3O+1 Acids are chemicals in which the positive ion is a hydrogen atom. HCl or H2SO4 When mixed with water they produce a free hydrogen ion that combines with a water molecule to produce a hydronium ion (H3O) H+1 + H2O  H3O+1 An acid is a substance that releases hydrogen ions when it breaks apart in water.

Physical Properties of Acids Taste sour React with metals to produce hydrogen 2HCl + 2Na  2NaCl + H2 Conduct electricity.

Bases Bases are substances in which the negative ion is an ion called hydroxide (OH)-1 For example; NaOH, or KOH used to make soap, household cleaners, fertilizers, and explosives.

Physical Properties of Bases Taste bitter Feel slippery Conduct electricity Sometimes Caustic. That is they eat away at certain substances and they are irritating or damaging to skin.

Salts A salt is a compound formed from the positive metal ions of a base and a negative nonmetal ion of an acid. NaCl, K2SO4 Are the product of a reaction between an acid and a base, along with water.

Physical Properties of Salts They form crystals when in solid form They usually have a higher hardness because of their ionic bonding. An acid plus a base yields a salt and water. HCl + NaOH  NaCl + HOH HCl + NaOH  NaCl + H2O

Neutralization A reaction between an acid and base. The products of a neutralization reaction are a salt and water.

The pH Scale The pH scale gives a measure of the concentration of positive hydrogen ions in a solution. a way of describing the acidic or basic strength of a solution. the acidity of a solution can be expressed by using the pH scale

The pH Scale the scale ranges from 0 to 14 acids range from 0 to 6, with 0 being the strongest acid bases range from 8 to 14, with 14 being the strongest base. pure water, which is neither acid nor base, has a pH level of 7 or is neutral

Indicators Indicators are substances that visibly show a change in the nature of a chemical system. Universal indicator- an acid/base indicator that shows, by color, the pH of a substance.

Indicators 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ACIDIC NEUTRAL BASIC