Test- Water/Solutions/A&B

Water molecule structure

One oxygen atom connected to two hydrogen atoms.

Polarity of water

Oxygen pulls harder on electrons, making one side slightly negative and the other slightly positive.

Hydrogen bonding

Water molecules sticking together.

Surface tension

The tight layer on water’s surface.

Surfactant

A substance that lowers surface tension.

Example of surface tension

Water drops forming beads or bugs walking on water.

Cause of water’s special properties

Hydrogen bonds between water molecules.

Aqueous solution

A solution with water in it.

Solvent

The liquid that dissolves something.

Solute

The substance being dissolved.

Substances that dissolve best in water

Ionic and polar substances.

"Like dissolves like"

Similar substances dissolve each other.

Example of "like dissolves like"

Salt dissolves in water.

Electrolyte

A substance that lets electricity flow in water.

Nonelectrolyte

A substance that does not let electricity flow in water.

Hydrate

A compound with water trapped inside it.

Anhydrous

Without water.

Desiccant

A material that absorbs water.

Factors affecting dissolving speed

Temperature, stirring, and smaller pieces.

Solubility

The most solute that can dissolve.

Factors affecting solubility

Temperature, pressure, and the type of substance.

Henry’s Law

More pressure = more gas dissolves.

Concentration

How much solute is in a solution.

Dilute solution

Has a small amount of solute.

Concentrated solution

Has a large amount of solute.

Qualitative terms

Words that describe, not exact numbers.

Molarity

Moles of solute per liter of solution. M={moles} / {liters}

How to calculate molarity

Divide moles by liters.

Preparing a molar solution

Dissolve the solute, then add water to the correct volume.

Effect of dilution

The amount of solute stays the same, but concentration decreases.

Dilution formula

M1V1=M2V2

Arrhenius acid

Makes H⁺ ions in water.

Arrhenius base

Makes OH⁻ ions in water.

Bronsted-Lowry acid

Gives away H⁺.

Bronsted-Lowry base

Accepts H⁺.

Ionizable hydrogen

A hydrogen that can break off as H⁺.

Six strong acids

HCl, HBr, HI, HNO₃, H₂SO₄, HClO₄.

Strong bases

Bases with Group 1 or 2 metals.

Hydronium ion formation

H⁺ joins with water to make H₃O⁺.

Amphoteric substance

Can act as an acid or a base.

Neutral solution

Equal amounts of H⁺ and OH⁻.

Kw

The relationship between H⁺ and OH⁻ in water: Kw=[H+][OH-]=1.0 x 10^-14

Acidic solution

More H⁺ than OH⁻.

Basic solution

More OH⁻ than H⁺.

pH

Measures how acidic or basic something is.

Finding H⁺ from pH

[H^+]=10^{-pH}.

pH and pOH relationship

pH+pOH=14.

Neutral pH

7.

Acidic pH

Below 7.

Basic pH

Above 7.

Methods to measure pH

pH paper and pH meter.

Limitation of indicators

They only estimate pH.

Indicator

A chemical that changes color at different pH levels.

Indicators used in class

Universal indicator and red cabbage juice.

Strong acid/base

Completely breaks apart in water.

Weak acid/base

Only partly breaks apart in water.

Strong vs. weak

How much it breaks apart.

Concentrated vs. dilute

Concentrated means a lot of solute dissolved in a solvent.
Dilute means only a little solute dissolved in a solvent.

Neutralization reaction

Acid + base → water + salt.

Salt solution classification

Depends on the acid and base used.