Chapter 3: Water & Life

1.I can explain the significance of polar covalent and hydrogen bonds within and between water molecules.

a. I can determine how many water molecules can bond with each other.

b. I can describe the four emergent properties of water and explain how each property effects life 1. Adhesion and cohesion2. Water moderates temperature

High specific heat Evaporative cooling High heat of vaporization

3. Water is a versatile solvent4. Water is less dense when it freezes.

Learning targets

Review: Polar Covalent, Non-Polar Covalent & Hydrogen Bonds

Hydrophilic Water loving Ex: salts, sugars, most

solubles Hydrophobic

Water fearing Ex: fats, oils, waxes

Terms to know: Hydrophilic & Hydrophobic

1. I can explain the significance of polar covalent and hydrogen bonds within and between water molecules.

a. I can determine how many water molecules can bond with each other.

b. I can describe the four emergent properties of water and explain how each property effects life 1. Adhesion and cohesion2. Water moderates temperature

High specific heat Evaporative cooling High heat of vaporization

3. Water is a versatile solvent4. Water is less dense when it freezes.

Learning targets

How many water molecules can bond with each other?

Practice…

What is the charge on this protein?

How do you know?

1. I can explain the significance of polar covalent and hydrogen bonds within and between water molecules.

a. I can determine how many water molecules can bond with each other.

b. I can describe the four emergent properties of water and explain how each property effects life 1. Adhesion and cohesion2. Water moderates temperature

High specific heat Evaporative cooling High heat of vaporization

3. Water is a versatile solvent4. Water is less dense when it freezes.

Learning targets

Cohesion Hydrogen bonds make water

“stick” to itself Adhesion

Hydrogen bonds make water “stick” to other polar or charged surfaces

1. Adhesion & Cohesion

Water transport in plants…. Transpiration Surface tension

Affect on Life

High specific heat It takes a lot of energy to change temp

Evaporative cooling When water molecules evaporate, the

remaining surface liquid cools High heat of vaporization

It takes a lot of energy to convert to gaseous state

2. Water Moderates Temperature

Climate control near large bodies of water Sweat dissipates body heat, transpiration

keeps plants cool

Affect on Life

Polar molecules mean water is attracted to charged and polar substances that can form H-bonds Hydrophilic = water loving

substances Hydrophobic = water hating

substances

3. Water is a versatile solvent

Chemical reactions involve or occur in water Biological fluids Cell membranes and homeostasis

Affect on Life

Water expands as it freezes H-bonds lock in place

4. Water is less dense as it freezes

Ice floats

Affect on Life

Adhesion, cohesion together allow water to “climb” in narrow spaces

5. Capillary Action

Water moves into and through small spaces Roots Leaves of plants (through xylem) Tears through tear ducts Absorption into paper towels

Affect on Life

Crash Course: Water- Liquid Awesome

2. I can describe how acids and bases affect living organisms.

a. I can determine the relationship between H+ and OH- in acidic, basic, and neutral solutions.

b. I can relate the relative amounts of H+ and OH- to the pH scale.

c. I can explain the logarithmic connection the pH scale.

d. I can explain what a buffer is, how it works and how it affects living organisms.

Learning Targets

Occasionally, water breaks apart into hydrogen and hydroxide ions

An imbalance of these ions leads to pH of solutions More H+ = acid More OH- = base

Disassociation of Water

Figure 3.10pH Scale

Battery acid

Gastric juice, lemon juice

Vinegar, wine,cola

BeerTomato juice

Black coffee

Rainwater

Urine

SalivaPure water

Human blood, tears

Seawater

Inside of small intestine

Milk of magnesia

Household ammonia

Householdbleach

Oven cleaner

Basicsolution

Neutralsolution

Acidicsolution

0

1

2

3

4

5

6

7

8

9

10

Neutral

[H+] = [OH]

Incr

easi

ng

ly B

asic

[H+]

< [

OH

]

Incr

easi

ng

ly A

cid

ic

[H+]

> [

OH

]H+H+

H+

H+H+

H+

H+

H+

OH

OH

H+

OH

H+

OH

OH

OHOH

H+H+

H+

H+

OHOH

OH

OH OHOH

OHH+

11

12

13

14

2. I can describe how acids and bases affect living organisms.

a. I can determine the relationship between H+ and OH- in acidic, basic, and neutral solutions.

b. I can relate the relative amounts of H+ and OH- to the pH scale.

c. I can explain the logarithmic connection the pH scale.

d. I can explain what a buffer is, how it works and how it affects living organisms.

Learning Targets

Minimizes changes to pH in a solution Example: carbonic acid in blood

If pH is too acidic: accepts access H+ ions If pH is too basic: donates H+ ions

Living organisms must maintain homeostasis!

Buffers