Water and pH

WaterWater’’s polar nature allows it to form s polar nature allows it to form hydrogen bonds. These bonds give hydrogen bonds. These bonds give

water many important qualities.water many important qualities.

Hydrogen Bonding of Water Molecules

Properties of Water Important to Life: Cohesion: ___________________________ Cohesion: ___________________________

______________________________________________________________________ Importance to living things:Importance to living things:

Creates _____________, which allows for Creates _____________, which allows for some organisms to walk on water. some organisms to walk on water.

Allows strings of water to be pulled up to Allows strings of water to be pulled up to the leaves in tall trees.the leaves in tall trees.

Properties of Water Important to Life: Cohesion: Cohesion: an attraction between molecules an attraction between molecules

of the same substanceof the same substance Importance to living things:Importance to living things:

Creates ______________Creates ______________,, which allows which allows for some organisms to walk on water. for some organisms to walk on water.

Allows strings of water to be pulled up to Allows strings of water to be pulled up to the leaves in tall trees.the leaves in tall trees.

Properties of Water Important to Life: Cohesion: Cohesion: an attraction between molecules an attraction between molecules

of the same substanceof the same substance Importance to living things:Importance to living things:

Creates Creates surface tension,surface tension, which allows which allows for some organisms to walk on water. for some organisms to walk on water.

Allows strings of water to be pulled up to Allows strings of water to be pulled up to the leaves in tall trees.the leaves in tall trees.

Properties of Water Important to Life: Adhesion-Adhesion-

Ever wonder why water in a glass Ever wonder why water in a glass graduated cylinder appears to climb up graduated cylinder appears to climb up the side of the cylinder? The water is the side of the cylinder? The water is attracted to the glass and sticks to it attracted to the glass and sticks to it through the process of adhesion.through the process of adhesion.

Properties of Water Important to Life: Adhesion-Adhesion-an attraction between molecules an attraction between molecules

of different substancesof different substances

Ever wonder why water in a glass Ever wonder why water in a glass graduated cylinder appears to climb up graduated cylinder appears to climb up the side of the cylinder? The water is the side of the cylinder? The water is attracted to the glass and sticks to it attracted to the glass and sticks to it through the process of adhesion.through the process of adhesion.

Adhesion (cont)

Importance to living Importance to living things:things: Water is attracted to Water is attracted to

the tubes in plants, the tubes in plants, called xylem, that called xylem, that carry it from the carry it from the roots to the leaves. roots to the leaves. As a result, it sticks As a result, it sticks to the sides of the to the sides of the tubes and resists tubes and resists gravity.gravity.

Properties of Water Important to Life: Ice is less dense than water.Ice is less dense than water.

Why? Why? Importance to living things:Importance to living things:

Ice floats allowing for Ice floats allowing for

Properties of Water Important to Life: Ice is less dense than water.Ice is less dense than water.

Why? Why? Water expands as it freezes.Water expands as it freezes. Importance to living things:Importance to living things:

Ice floats allowing for Ice floats allowing for

Properties of Water Important to Life: Ice is less dense than water.Ice is less dense than water.

Why? Why? Water expands as it freezes.Water expands as it freezes.

Importance to living things:Importance to living things:Ice floats allowing for Ice floats allowing for fish and fish and

underwater plant life to survive in underwater plant life to survive in regions with cold wintersregions with cold winters

Properties of Water Important to Life: Water is an excellent Water is an excellent solventsolvent..

Solution- Solution-

2 parts:2 parts:SolventSolvent--Solute-Solute-

Properties of Water Important to Life: Water is an excellent Water is an excellent solventsolvent..

Solution- Solution- mixture of two or more mixture of two or more substances in which the molecules of the substances in which the molecules of the substances are evenly distributedsubstances are evenly distributed

2 parts:2 parts:SolventSolvent--Solute-Solute-

Properties of Water Important to Life: Water is an excellent Water is an excellent solventsolvent..

Solution- Solution- mixture of two or more mixture of two or more substances in which the molecules of the substances in which the molecules of the substances are evenly distributedsubstances are evenly distributed

2 parts:2 parts:SolventSolvent-- the substance that dissolvesthe substance that dissolvesSolute-Solute-

Properties of Water Important to Life: Water is an excellent Water is an excellent solventsolvent..

Solution- Solution- mixture of two or more mixture of two or more substances in which the molecules of the substances in which the molecules of the substances are evenly distributedsubstances are evenly distributed

2 parts:2 parts:SolventSolvent-- the substance that dissolvesthe substance that dissolvesSolute-Solute-the substance that is dissolvedthe substance that is dissolved

Properties of Water Important to Life: What dissolves in water?What dissolves in water?

““Like dissolves like.Like dissolves like.”” Polar water dissolves Polar water dissolves

These substances are called These substances are called

Examples include Examples include

Properties of Water Important to Life: What dissolves in water?What dissolves in water?

““Like dissolves like.Like dissolves like.”” Polar water dissolves Polar water dissolves both ionic compounds both ionic compounds

and other polar moleculesand other polar molecules These substances are called These substances are called

Examples include Examples include

Properties of Water Important to Life: What dissolves in water?What dissolves in water?

““Like dissolves like.Like dissolves like.”” Polar water dissolves Polar water dissolves both ionic compounds both ionic compounds

and other polar moleculesand other polar molecules These substances are called These substances are called

hydrophilichydrophilic Examples include Examples include

Properties of Water Important to Life: What dissolves in water?What dissolves in water?

““Like dissolves like.Like dissolves like.”” Polar water dissolves Polar water dissolves both ionic compounds both ionic compounds

and other polar moleculesand other polar molecules These substances are called These substances are called

hydrophilichydrophilic Examples include Examples include sugar and saltsugar and salt

Properties of Water Important to Life: Polar water does NOT dissolve Polar water does NOT dissolve

These substances are called These substances are called

Examples include Examples include

Properties of Water Important to Life: Polar water does NOT dissolve Polar water does NOT dissolve nonpolar nonpolar

compoundscompounds

These substances are called These substances are called

Examples include Examples include

Properties of Water Important to Life: Polar water does NOT dissolve Polar water does NOT dissolve nonpolar nonpolar

compoundscompounds

These substances are called These substances are called hydrophobichydrophobic

Examples include Examples include

Properties of Water Important to Life: Polar water does NOT dissolve Polar water does NOT dissolve nonpolar nonpolar

compoundscompounds

These substances are called These substances are called hydrophobichydrophobic

Examples include Examples include oil and waxoil and wax

pH

Key Idea: pH is the measure of the amount Key Idea: pH is the measure of the amount of hydrogen ions (H+) in a solutionof hydrogen ions (H+) in a solution

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Amount of H+ in solution

Amount of OH- in solution

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+

Amount of H+ in solution

Amount of OH- in solution

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

Amount of OH- in solution

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+

Amount of OH- in solution

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

Low OH-

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

Low OH- High OH-

pH range

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

Low OH- High OH-

pH range Below 7

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

Low OH- High OH-

pH range Below 7 Above 7

Examples

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

Low OH- High OH-

pH range Below 7 Above 7

Examples Lemon juice, HCl, Soda

pH

Characteristic Acid Base

Accepts or donates H+ to the solution

Donates H+ Accepts H+

Amount of H+ in solution

High H+ Low H+

Amount of OH- in solution

Low OH- High OH-

pH range Below 7 Above 7

Examples Lemon juice, HCl, Soda Bleach, Ammonia, NaOH

…great…so how do I remember this stuff?

0 7 14

Strong A

cid

Wea

k Acid

Strong

Bas

e

Wea

k Base

Acid Base

Neutral

No really…how do I do it?

HH HH

H

H

OHOHOHOH

0 7 14

Random factoids

pH

It is a logarithmic scale, meaning each It is a logarithmic scale, meaning each number is a power of 10number is a power of 10

pH

It is a logarithmic scale, meaning each It is a logarithmic scale, meaning each number is a power of 10number is a power of 10

For example, a solution with a pH of 5 has For example, a solution with a pH of 5 has 10 times more H+ ions than a solution with 10 times more H+ ions than a solution with a pH of 6a pH of 6

pH Practice

Is lemon juice, with a pH of 2.5, an acid, Is lemon juice, with a pH of 2.5, an acid, base or neutral? ______________________base or neutral? ______________________

pH Practice

Is lemon juice, with a pH of 2.5, an acid, Is lemon juice, with a pH of 2.5, an acid, base or neutral? base or neutral? AcidAcid

pH Practice

Is lemon juice, with a pH of 2.5, an acid, Is lemon juice, with a pH of 2.5, an acid, base or neutral? base or neutral? AcidAcid

Which has a higher concentration of H+ Which has a higher concentration of H+ ions: a solution with a pH of 12 or a ions: a solution with a pH of 12 or a solution with a pH of 8? solution with a pH of 8?

pH Practice

Is lemon juice, with a pH of 2.5, an acid, Is lemon juice, with a pH of 2.5, an acid, base or neutral? base or neutral? AcidAcid

Which has a higher concentration of H+ Which has a higher concentration of H+ ions: a solution with a pH of 12 or a ions: a solution with a pH of 12 or a solution with a pH of 8? solution with a pH of 8? 88

pH Practice

Is lemon juice, with a pH of 2.5, an acid, base Is lemon juice, with a pH of 2.5, an acid, base or neutral? or neutral? AcidAcid

Which has a higher concentration of H+ ions: a Which has a higher concentration of H+ ions: a solution with a pH of 12 or a solution with a solution with a pH of 12 or a solution with a pH of 8? pH of 8? 88

Is bleach, with a pH of 12.5, an acid, base or Is bleach, with a pH of 12.5, an acid, base or neutral? neutral?

pH Practice

Is lemon juice, with a pH of 2.5, an acid, Is lemon juice, with a pH of 2.5, an acid, base or neutral? base or neutral? AcidAcid

Which has a higher concentration of H+ Which has a higher concentration of H+ ions: a solution with a pH of 12 or a ions: a solution with a pH of 12 or a solution with a pH of 8? solution with a pH of 8? 88

Is bleach, with a pH of 12.5, an acid, base Is bleach, with a pH of 12.5, an acid, base or neutral? or neutral? BaseBase

pH Practice

If you were to decrease the pH of a solution If you were to decrease the pH of a solution from 6 to 4, how many times greater will from 6 to 4, how many times greater will the concentration of hydrogen ions be? the concentration of hydrogen ions be?

pH Practice

If you were to decrease the pH of a solution If you were to decrease the pH of a solution from 6 to 4, how many times greater will from 6 to 4, how many times greater will the concentration of hydrogen ions be? the concentration of hydrogen ions be?

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