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9m mmmg

Name: Navardo White

Grade: 9BH

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An acid is a substance which reacts with a base.

Commonly, acids can be identified as tasting sour,

reacting with metals such as calcium, and bases like

sodium carbonate. Aqueous acids have a pH of less than

7, where an acid of lower pH is typically stronger.

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There are two general types of acids:

Strong Acids and Weak Acids

Strong acids are considered strong because they dissociate completely

in water to form the same number of moles of hydrogen ions (H+) as

the number of moles of acid added to water. Therefore, for a strong

acid, you can determine the pH of the solution simply by knowing the

concentration of the acid.

Weak acids on the other hand, do not dissociate completely in water.

Some examples of weak acids are acetic acid (found in vinegar),

carbonic acid, hydrofluoric acid, and formic acid. Note that just because

an acid is called "weak" does NOT mean that it is not dangerous!

Hydrofluoric acid (HF) is a weak acid and is one of the most dangerous

acids of all of them! In order to determine the pH of a solution of a

weak acid, you must know two things: the concentration of the acid in

the solution, and also something called the Ka of the acid (or

equivalently the pKa, which is just equal to -log10Ka). The Ka is a

measure of how much the acid will dissociate. A higher Ka value (and a

lower pKa!) means that the acid will dissociate more.

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A base in chemistry is a substance that can accept

hydrogen ions (protons or more generally, donate

electron pairs. A soluble base is referred to as an

alkali if it contains and releases hydroxide ions

(OH) quantitatively.

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Two Types of Bases: OH

H3O+

This imbalance can be created in two different ways.

First, the base can be a hydroxide, which merely dissociates to yield

hydroxide ions:

Where M represents the cation, usually a metal. The most familiar bases

are such hydroxides.

The second type of base acts by extracting a hydrogen ion from a water

molecule, leaving a hydroxide ion:

An example of this second type of base that is not a hydroxide can be an

ammonia molecule in water (aqueous ammonia):

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Ammonia acts as a base by stripping a proton from a water molecule,

leaving an increased OH

concentration. Notice in the equilibrium

reaction that and NH3 are a conjugate acid-base pair, related by

transferring a single proton. Similarly, water acts as an acid by donating

a proton to ammonia. H2O and OH

is a conjugate acid-base pair, related

by the loss of a single proton.

Alternatively, the base may be a particular kind of negative ion with a

high attraction for a hydrogen ion:

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Acids are H+ donors and Bases are H+ acceptors in chemical

processes. Example: HCl gives H+ in the solvent water to

become H+ and Cl- and is an acid. This is only one of several

definitions of acids and bases but in my opinion the easiest to

understand.

Also, acids have a pH below 7 and bases have a pH above 7.

The pH means the molar concentration of [H+] ions, 1 pH

meaning 1 * 10 ^ -1 moles of [H+] ions per liter and 2 pH

meaning 1 * 10 ^ -2 moles per liter. So, each 1 decrease on the

pH scale means 10 times more [H+] ions and each 1 increase

means 10 times less [H+] ions.

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.

They are important because everything in our world is affected

by them. We couldnt not live in a world that is either too acidic

or too base. Think about heart burn, to treat heart burn, we

have to have an understanding of acids and bases.

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Acids and bases have a wide variety of uses in both our

everyday home lives and in chemistry and industry. The reason

is twofold. First, since they are on the polar ends of the pH

scale (the scale that measures the concentration of Hydrogen

molecules) they are highly reactive and corrosive. Secondly,

their type of bonding, ionic, is very useful in chemistry to form

other chemicals and help drive reactions.