Properties of solutions, acids and based

Acid

Releases hydrogen ions (H+) in water; sour taste; turns blue litmus red; pH less than 7.

Base

Releases hydroxide ions (OH-) in water; bitter taste; slippery feel; turns red litmus blue; pH greater than 7.

pH scale

Measures how acidic or basic a solution is; ranges from 0–14.

Acidic pH

pH less than 7.

Neutral pH

pH equal to 7 (pure water).

Basic pH

pH greater than 7; also called alkaline.

Strength of acids and bases

The farther from pH 7, the stronger the acid or base.

Examples of acids

Lemon juice, stomach acid (HCl).

Examples of bases

Baking soda solution, soapy water, bleach.

Neutralization reaction

Reaction between an acid and a base to form water and a salt.

Litmus test

Acids turn blue litmus red; bases turn red litmus blue.

Buffers

Chemicals that resist changes in pH by absorbing or releasing H+.

Blood pH

Normal blood pH is about 7.35–7.45 (slightly basic).

Solution

A homogeneous mixture where one substance is dissolved in another.

Solute

The substance that gets dissolved (smaller amount).

Solvent

The substance that does the dissolving (larger amount), often water.

Aqueous solution

A solution where water is the solvent.

Concentration

How much solute is dissolved in a solvent (strength of a solution).

Dilute solution

A solution with a small amount of solute.

Concentrated solution

A solution with a large amount of solute.

Solubility

How much solute can dissolve in a solvent at a given temperature.

Temperature and solubility

Solubility usually increases when temperature increases.

Polar molecule

Has uneven charge; water is polar; attracts other polar substances and ions.

Like dissolves like

Polar dissolves polar; nonpolar dissolves nonpolar.

Electrolyte

A substance that dissolves in water and conducts electricity (like salts).

Nonelectrolyte

A substance that dissolves in water but does NOT conduct electricity (like sugar).

Suspension

Mixture where particles are large and settle out (not a true solution).

Colloid

Mixture with medium particles that do not settle (milk, fog).