Section 3.4

Acids are chemicals in which the positive ion is a hydrogen atom.

for example; 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.

1. Taste sour

2. React with metals to produce hydrogen

2HCl + 2Na 2NaCl + H2

3. Conduct electricity.

Bases are substances in which the negative ion is an ion called hydroxide (OH)-1.

For example; NaOH, or KOHused to make soap, household

cleaners, fertilizers, and explosives.

1. Taste bitter2. Feel slippery3. Conduct electricity4. Sometimes Caustic. That is they eat

away at certain substances and they are irritating or damaging to skin.

A salt is a compound formed from the positive metal ions of a base and a negative nonmetal ion of an acid.

For example NaCl, K2SO4 Are the product of a reaction between an

acid and a base, along with water.

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 + HOHor HCl + NaOH NaCl + H2O

After neutralization, an acid-base mixture is not as acidic or basic as the individual starting solutions were.

The final pH depends on such factors as the volumes, concentrations, and identities of the reactants. For example, some acids and bases react to form products that are not neutral. If only a small amount of strong base is reacted with a much larger amount of strong acid, the solution will remain acidic.

In a neutralization reaction, an acid reacts with a base to produce a salt and water

the scale ranges from 0 to 14 acids range from 0 to 7, with 0 being the

strongest acid bases range from 7 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

The pH scale gives a measure of the concentration of positive hydrogen ions in a solution.

A low pH tells you that the concentration of hydrogen ions is high. In contrast, a high pH tells you that the concentration of hydrogen ions is low.

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

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.

ACIDIC NEUTRAL BASIC

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