Solutions

Solution

A solution is a homogeneous mixture in which one substance is dissolved in another substance

Components of a solution

Two parts of a solution: the substance being dissolved (solute) and the substance doing the dissolving (solvent)

Aqueous solution

Solutions in which the solvent is water are aqueous solutions (most common)

Tinctures

A solution in which the solvent is alcohol is a tincture Ex: iodine tincture

Characteristics of a solution

Mixture of two or more substances

light passes through it particles are uniformly distributed

Ions and dissociation

Ions are atoms with a positive or negative charge

Electrolytes

Solutions that conduct electricity are electrolytes (sodium chloride and silver nitrate)

Non-electrolytes

Non-electrolytes form solutions that do not conduct electricity (sugar, alcohol, benzene)

Questions

What is a solution? What are the two parts of a solution?

What are three properties of a solution?

Questions

What’s the difference between an aqueous solution and a tincture

Question

If you wanted to dissolve a substance in water as quickly as possible what could you do?

Ways to increase dissolving rate

In order to increase the rate in which a solution dissolves one could heat the solution, stir it, or crush the solute particles

Solubility

The measure of how much solute can be dissolved in a solvent is solubility

What affects solubility?

The three main factors that affect solubility are temperature, type and the amount of the solvent

Effervescence (fizz)

The escape of a gas from a liquid is effervescence (example: soda and alka seltzer)

Concentration

Concentration of a solution is the amount of solute that is dissolved in a solvent

Concentrated vs. dilute

A solution with a lot of solute dissolved is concentrated

A solution with a little solute dissolved is dilute

Types of solutions

A saturated solution contains all the solute it can possibly hold

An unsaturated solution contains less solute that is possible

Supersaturated solution

A supersaturated solution can be made to hold more solute than is normal

Question

Compare a saturated, unsaturated, and a supersaturated solution

Questions

What is solubility and what are the three factors that affect it?

What are three ways to increase the rate in which a solute dissolves?

Water

Water is the universal solvent

A substance that cannot dissolve in water is insoluble

Polar vs. non-polar

A polar molecule has oppositely charged ends (+ and -)

Non-polar molecules have the same charges on its ends

Rule for dissolving solutes in a solvent

Like solutes dissolve in like solvents (polar in polar, non-polar in non-polar)

Hard water vs. soft water

Hard water contains dissolved metal ions

Soft water does not contain dissolved metal ions

Freezing point depression

Lowering the freezing point of a solution as a result of the dissolved solute (freezing point depression) Ex: antifreeze in water

Boiling point elevation

Raising the boiling point of a substance by adding solute (salt in water)

Questions

What is the difference between polar and non-polar molecules?

What is the general rule for dissolving solutes?

Questions

What is the difference between hard and soft water?

How does a solute affect the freezing point and the boiling point?

Suspension

A suspension is a heterogeneous mixture in which the solute particles are large enough to be seen (solute is suspended)

Colloid

A colloid is a homogeneous mixture that is not a true solution (does not separate, solute remains suspended)

Acids

Properties of an acid: sour taste, affecting the color of indicators, turn litmus paper from blue to red, pH 1-6.9

Weak acids vs. strong acids

Weak acids (pH 4 - 6.9) Strong acids (pH about 1-3; common acids: sulfuric, hydrochloric, nitric, and acetic acids

Bases

Bases are slippery, bitter taste, turn litmus paper from red to blue

pH 7.1-14

Bases

Common bases potassium hydroxide, calcium hydroxide, sodium hydroxide, and ammonium hydroxide

Weak bases vs. strong bases

Weak bases (7.1-10.9 pH)

Strong bases (11-14 pH)

pH scale Measures hydronium ion concentration (strength of the acid or base)

pH scale ranges from 0-14 (7 is the neutral point) water

Salt

Salt is a compound formed when an acid is mixed with a base (positive ion from a base and a negative ion from an acid)

Neutralization

A neutralization reaction occurs when an acid and a base combine to form salt and water

Precipitate

A precipitate is an insoluble substance crystallizes out of solution (ex: salt from a neutralization reaction)

Precipitation reaction

The process of forming a precipitate is precipitation

Questions

What is the pH scale used for?

What is the pH range for an acid, a base?

Questions

What are some properties of an acid? Of a base?

Describe neutraliztion. What is a salt?