Properties of Water

Front

Molecule Noun

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[mol-uh-kyool]

Back

Molecule

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The smallest fundamental unit of a chemical compound, formed when two or more atoms are chemically bonded together.

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Example: This diagram shows a water molecule (H₂O), which is made of one oxygen atom bonded to two hydrogen atoms, the basic unit of water.

Front

Polar Molecule Noun

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[poh-ler mol-uh-kyool]

Back

Polar Molecule

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A molecule in which electric charge is unevenly distributed, creating a positive end and a negative end.

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Example: A water molecule is polar because its atoms have an uneven electrical charge, with a negative side (oxygen) and a positive side (hydrogen).

Front

Hydrogen Bond Noun

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[hy-druh-jen bond]

Back

Hydrogen Bond

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A weak attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge.

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Example: This diagram shows how a hydrogen bond (dashed line) forms between the hydrogen atom of one water molecule and the oxygen atom of another.

Front

Cohesion Noun

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[koh-hee-zhun]

Back

Cohesion

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The intermolecular attraction between molecules of the same substance, causing them to stick together.

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Example: This diagram shows how water molecules are attracted to each other by hydrogen bonds, causing them to stick together, which is the property of cohesion.

Front

Adhesion Noun

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[ad-hee-zhun]

Back

Adhesion

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The force of attraction between molecules of different substances, causing them to cling to each other.

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Example: This diagram shows water climbing up a narrow tube because of adhesion, the force that attracts water molecules to the surface of the glass tube.

Front

Surface Tension Noun

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[sur-fis ten-shun]

Back

Surface Tension

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A property of liquids caused by cohesive forces between molecules at the surface, creating a thin, elastic-like film.

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Example: A water strider stands on water due to surface tension. Below, a diagram shows surface water molecules are pulled inward, creating a strong, skin-like layer.

Front

Capillary Action Noun

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[kap-uh-ler-ee ak-shun]

Back

Capillary Action

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The movement of a liquid along a solid surface, caused by the combined forces of cohesion and adhesion.

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Example: Water moves up the paper towel from one glass to another, against gravity, demonstrating capillary action through the small spaces in the paper.

Front

Heat Capacity Noun

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[heet kuh-pas-i-tee]

Back

Heat Capacity

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The amount of heat energy required to raise the temperature of a given quantity of a substance by one degree.

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Example: A large mass of water (like an ocean) requires more heat to raise its temperature than a small mass (like a glass of water).

Front

Mixture Noun

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[miks-cher]

Back

Mixture

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A material composed of two or more substances that are physically mixed together but not chemically combined.

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Example: This diagram shows a solution, which is a type of mixture where one substance (the solute) is evenly mixed into another (the solvent).

Front

Solution Noun

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[suh-loo-shun]

Back

Solution

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A type of homogeneous mixture in which all the components are evenly distributed at a molecular level.

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Example: This diagram shows a solution, where solute particles (pink) are evenly mixed and dissolved within the solvent particles (blue), like salt in water.