Biology Quiz 2.2: Water as a Universal Solvent

Questions and Answers

Why is water called the universal solvent?

It is capable of dissolving more substances than any other liquid due to its chemical composition and physical attributes.

Like dissolves like. Therefore, oil dissolves in water.

False

Why don't oil and water mix?

Oil is denser than water.

Water is polar and oil is non-polar. (correct)

Oil evaporates quickly.

Water and oil have similar polarities.

What charges do water molecules have?

The oxygen side is slightly negative and the hydrogen side is slightly positive. Signup and view all the answers

What does pH indicate?

Hydrogen ion concentration. Signup and view all the answers

What is a covalent bond?

A chemical bond that involves sharing a pair of electrons between atoms. Signup and view all the answers

Define solution.

A homogeneous mixture of two or more substances. Signup and view all the answers

What is a solute?

A substance that is dissolved in a solution. Signup and view all the answers

What is a solvent?

A liquid substance capable of dissolving other substances. Signup and view all the answers

What is a hydrogen bond?

A weak attraction between a hydrogen atom and another atom. Signup and view all the answers

What is cohesion?

Attraction between molecules of the same substance. Signup and view all the answers

What is adhesion?

An attraction between molecules of different substances. Signup and view all the answers

What is an acid?

A substance that increases the hydrogen ion concentration of a solution. Signup and view all the answers

What is a base?

A substance that decreases the hydrogen ion concentration in a solution. Signup and view all the answers

Define capillary action.

The attraction of the surface of a liquid to the surface of a solid. Signup and view all the answers

What is a polar molecule?

A molecule that has electrically charged areas. Signup and view all the answers

What is a non-polar molecule?

A molecule that shares electrons equally and does not have oppositely charged ends. Signup and view all the answers

What does the pH scale measure?

It indicates the concentration of hydrogen ions (H+) in a solution and ranges from 0 to 14. Signup and view all the answers

What is low pH associated with?

Acid. Signup and view all the answers

What is high pH associated with?

Basic. Signup and view all the answers

Study Notes

Water as a Universal Solvent

Water can dissolve more substances than any other liquid due to its unique chemical composition and physical properties.
The polar arrangement of oxygen (negative charge) and hydrogen (positive charge) in water allows it to attract various molecules.

Polarity and Dissolution

Water is classified as a polar molecule, while oil is non-polar, resulting in water's inability to dissolve oil.
Salt, being ionic and highly polar, dissolves well in water due to the principle "like dissolves like," where polar substances dissolve other polar substances.

Oil and Water Separation

Oil and water do not mix because of their differing polarities; oil is less dense and floats on top of water.
The strong attraction between water molecules (cohesion) inhibits their attraction to oil molecules.

Characteristics of Water Molecules

Water molecules exhibit polarity, with the oxygen end slightly negative and the hydrogen end slightly positive.

Key Chemical Concepts

pH indicates the hydrogen ion concentration in a solution, typically measured on a scale from 0 (acid) to 14 (basic).
A covalent bond involves the sharing of electron pairs between atoms.
A solution is a homogeneous mixture of two or more substances, with the solute being the substance dissolved in the solvent (the dissolving liquid).

Types of Bonds and Interactions

Hydrogen bonds are weak attractions between a hydrogen atom and another atom, influencing various properties of water.
Cohesion refers to the attraction between molecules of the same substance, while adhesion is the attraction between different substances.

Acids and Bases

Acids increase hydrogen ion concentration in a solution, while bases decrease it.
A low pH indicates an acidic solution, whereas a high pH indicates a basic solution.

Additional Properties

Capillary action describes how liquid rises or moves in narrow spaces due to the attraction between the liquid's surface and that of a solid.
Polar molecules have charged areas, while non-polar molecules share electrons equally, lacking charged ends.

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Description

Test your knowledge on the properties of water, particularly why it is known as the universal solvent. This quiz explores the chemical composition and polar arrangement of water molecules that contribute to its unique dissolving capabilities. Challenge yourself with flashcards that cover essential concepts related to water in biology.