Water: Essential for Life and Its Phases

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Questions and Answers

What percentage of Earth's surface is currently covered in water?

71% (correct)

81%

61%

91%

Which phase of water is the least abundant on Earth?

Liquid

Solid

Freshwater (correct)

Gas

What is the primary location of Earth's freshwater resources?

In rivers and lakes

In soil moisture

In the atmosphere

In groundwater (correct)

What percentage of water in most adult bodies is made up of water?

55-60% Signup and view all the answers

Which organ in the human body contains the highest percentage of water?

Lungs Signup and view all the answers

What is the main component of water as a molecule?

H2O Signup and view all the answers

Which method is NOT used for making non-drinkable water usable?

Evaporation Signup and view all the answers

What fraction of Earth's freshwater is found in glaciers and ice caps?

68% Signup and view all the answers

What is the primary characteristic of dipole-dipole attraction?

It requires alignment of partially positive and negative charges. Signup and view all the answers

Which of the following statements best defines hydrogen bonding?

It is a strong attraction among molecules with hydrogen bound to very electronegative atoms. Signup and view all the answers

What role do electronegative atoms play in molecular interactions?

They create permanent dipoles by attracting electrons. Signup and view all the answers

In which scenarios do strong hydrogen bonds primarily form?

When hydrogen is combined with highly electronegative oxygen, nitrogen, or fluorine. Signup and view all the answers

What phase states can water naturally occur in on Earth?

As a solid, liquid, and gas. Signup and view all the answers

Which of the following describes the effects of hydrogen bonding on water's behavior?

It contributes to water's high surface tension and boiling point. Signup and view all the answers

What minimizes repulsion between molecules during hydrogen bonding?

Positioning of partially charged ends of molecules. Signup and view all the answers

What is a key feature of molecules that exhibit dipole-dipole attractions?

They are polar and possess partial charges. Signup and view all the answers

What percentage of Canada's surface area is covered by lakes and rivers?

12% Signup and view all the answers

Which concept describes the bonding within a water molecule?

Covalent bonds Signup and view all the answers

How much of the global fresh surface water is contained in the Great Lakes?

18% Signup and view all the answers

What fraction of Canadians rely on groundwater for drinking water?

25% Signup and view all the answers

What type of bonding occurs between atoms within a water molecule?

Covalent bonding Signup and view all the answers

Which term refers to the interactions between multiple water molecules?

Intermolecular forces Signup and view all the answers

What is the main type of interaction that keeps water molecules together?

Hydrogen bonding Signup and view all the answers

What does the term 'phase changes' refer to in the context of water?

Transitions between solid, liquid, and gas states Signup and view all the answers

What remains intact when water changes its physical state?

The individual water molecules Signup and view all the answers

Which statement best describes the nature of water molecules?

Water molecules are polar, with the oxygen being electron-rich. Signup and view all the answers

How does the presence of intermolecular forces affect physical state changes in water?

They do not change the structure of water molecules. Signup and view all the answers

What is the charge of the oxygen atom in a water molecule?

It is partially negative. Signup and view all the answers

What does the term 'dipole' refer to in the context of water?

The unequal distribution of electron density within the molecule. Signup and view all the answers

In dipole-dipole attraction, what interactions are maximized?

Attractive positive-negative interactions. Signup and view all the answers

Which aspect of water's molecular structure contributes to its polarity?

The unequal sharing of electrons in covalent bonds. Signup and view all the answers

What is the representation for a partially positive charge in water molecules?

δ+ Signup and view all the answers

Study Notes

Water: Background

Water is essential for all life on Earth
71% of Earth's surface is covered by water
Oceans hold 96.5% of Earth's water
Remaining water exists as: freshwater in rivers and lakes, frozen water in glaciers and ice caps, soil moisture, groundwater aquifers, and water vapor in the atmosphere

Water: Background (Phases)

Water occurs naturally as a solid, liquid, or gas (three phases/physical states)
Currently, water exists as a solid (ice, snow), liquid (rain, surface water, groundwater), and gas (water vapor, humidity)
Surface water is found on top of land (e.g., streams, rivers, lakes, wetlands)
Groundwater is located beneath Earth's surface, in rock and soil pore spaces and fractures
Seawater is water from a sea or ocean

Water: Background (Definitions)

A molecule is two or more atoms bonded together.
Water (H₂O) is a molecule composed of three atoms bonded together.
Water exists in three physical states: solid (ice), liquid (water), and gas (water vapor).
Aqueous solutions are dissolved in water.

Water: Some Numbers

Humans are primarily composed of water
Newborn babies are about 78% water
One-year-old infants are about 65% water
Adults are 55-60% water (fat contains less water than muscle)
Water percentage in organs:
- Lungs: 83%
- Kidneys: 79%
- Brain: 73%
- Heart: 73%
Water percentage in the body decreases with age

Water: Some Numbers (Geology)

Freshwater: less than 1,000 milligrams per liter of dissolved solids (mostly salt)
Less than 3% of Earth's water is freshwater
Freshwater sources:
- Glaciers/ice caps: >68%
- Groundwater: ~30%
- Surface water: ~0.3%
Most accessible drinking water comes from 0.3% of 3% of Earth's water

Water: Some Numbers (Canada)

Canada has abundant freshwater resources
About 20% of the world's surface water is in Canada
Canada's lakes and rivers cover 12% of the surface area
Canada has more "lake area" than any other country
The Great Lakes contain 18% of global fresh surface water
25% of Canadians depend on groundwater for drinking water

Water: Essential Concepts

Intermolecular Forces (Hydrogen Bonding)*
Intermolecular forces are important interactions between molecules.
Hydrogen bonding is a type of intermolecular force that is stronger than other dipole-dipole interactions.
Hydrogen bonds occur when hydrogen is bonded to a highly electronegative atom (oxygen, nitrogen, or fluorine).

Water: Phase Changes

Three phases of water: solid, liquid, and gas
Phase changes occur between these states, like melting, freezing, evaporation, condensation, sublimation, and deposition.
When a substance changes state, the molecules remain intact, but the intermolecular forces change, not the molecules themselves.

Water: Phase Changes (Density)

Ice is less dense than liquid water

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Description

Explore the fundamental importance of water for life on Earth, its distribution across the planet, and its various phases as solid, liquid, and gas. Understand the different forms of water found in nature, including surface water, groundwater, and seawater. This quiz covers the essential definitions and characteristics of water.