Chemistry of Water and Its Properties

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Questions and Answers

What results from the uneven sharing of electrons in a water molecule?

It forms dipoles. (correct)

It changes chemical properties.

It increases temperature.

It becomes charged.

What type of bond forms between water molecules due to their polarity?

Ionic bonds

Covalent bonds

Metallic bonds

Hydrogen bonds (correct)

Which property of water allows it to be an excellent solvent?

It has low surface tension

The presence of ionic bonds

Its high density

Its polar nature (correct)

Why does ice float on water?

Liquid water expands when frozen. Signup and view all the answers

What contributes to the high specific heat capacity of water?

Presence of hydrogen bonds Signup and view all the answers

What effect does the polarity of water have on its surface tension?

Increases surface tension Signup and view all the answers

Which of the following roles does water play in living organisms?

It acts as a reagent. Signup and view all the answers

What causes water molecules to have an asymmetrical shape?

Uneven electron sharing. Signup and view all the answers

What property of water allows it to dissolve substances effectively?

Polarity Signup and view all the answers

Why is water's high specific heat capacity essential for living organisms?

It prevents large temperature fluctuations, maintaining a stable environment. Signup and view all the answers

What is the specific heat capacity of water?

4200 J/kg°C Signup and view all the answers

How does water contribute to temperature regulation in the body?

By transferring heat without significant temperature change. Signup and view all the answers

What role does water play in diffusion within prokaryotic cells?

It allows for the efficient transport of metabolites. Signup and view all the answers

What is the latent heat of vaporization in relation to water?

It is the energy required to break hydrogen bonds and change water from liquid to gas. Signup and view all the answers

What advantage does water's ability to absorb a lot of heat provide aquatic environments?

It creates stable habitats with minimal temperature fluctuations. Signup and view all the answers

Which type of molecules does water not transport efficiently due to hydrophobic properties?

Non-polar molecules Signup and view all the answers

Study Notes

Structure of Water

Water is composed of one oxygen atom and two hydrogen atoms.
Oxygen and hydrogen atoms share electrons (covalent bonding).
Oxygen attracts electrons more strongly, creating a slightly negative charge (δ-) on oxygen and slightly positive charges (δ+) on hydrogen.
This unequal charge distribution forms a dipole.
Water is a polar molecule—one end is negative, the other is positive.

Hydrogen Bonding in Water

Hydrogen bonds form between water molecules.
These bonds form between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another.
Hydrogen bonds are individually weak, but numerous ones create a strong structure.
Constantly break and reform.

Properties of Water Due to Hydrogen Bonds

Excellent solvent: Polar nature dissolves many substances (ions, polar molecules).
Transport medium: Essential for moving substances around organisms.
High specific heat capacity: Requires a large amount of energy to change water temperature; stable temperature for organisms.
High latent heat of vaporisation: Large amount of energy to convert liquid water to gas; helps regulate temperature through sweating/evaporation.
Lower density as a solid (ice): Ice floats; crucial for aquatic life.
High surface tension and cohesion: Water molecules stick together; crucial for transport.
Reagent: Water is involved in many biological reactions.

Water as a Solvent

Water's polarity makes it a "universal solvent" for polar substances.
Dissolves ions (e.g., sodium chloride) and polar molecules (e.g., glucose).
Enables chemical reactions in cells by making solutes more reactive.
Crucial for transport of metabolites (except non-polar).

High Specific Heat Capacity

A high specific heat capacity (4200 J/kg°C) means considerable energy is needed to change water temperature.
Stabilizes habitats and body temperatures, as it resists temperature fluctuations.
Essential for enzyme activity and maintaining constant internal temperatures in living organisms.
Water in blood plasma/tissue fluid aids temperature regulation.

Latent Heat of Vaporisation

Requires substantial energy to evaporate water, breaking hydrogen bonds.
Important for regulating an organism's temperature through evaporative cooling.

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Description

This quiz explores the structure of water, including its molecular composition and the significance of hydrogen bonding. It also delves into the unique properties of water that arise from these interactions, such as its solvent capabilities and high specific heat capacity.