Question

What is meant by the terms composition and structure when referring to matter?

Short answer

Composition refers to the elements or substances that constitute a specific type of matter and their respective proportions, such as the two hydrogen atoms and one oxygen atom in a water molecule. Structure, on the other hand, describes the arrangement and bonding of the atoms or molecules within the matter, like the spatial arrangement of hydrogen and oxygen atoms in a water molecule or the three-dimensional lattice of sodium and chloride ions in a sodium chloride crystal.

Step-by-step solution

Composition - Definition and Examples

Composition, when referring to matter, means the elements or substances that make up a particular type of matter and their respective proportions. For example, composition can be used to describe the elements and their proportions in a molecule, compound, or a mixture. Water (H₂O) has a composition of two hydrogen atoms (H) and one oxygen atom (O), while a mixture of nitrogen gas (N₂) and oxygen gas (O₂) may have a composition of 80% nitrogen and 20% oxygen, by volume.

Structure - Definition and Examples

Structure, when referring to matter, is the arrangement of the atoms or molecules that constitute the matter. Structure can be used to describe the way these atoms or molecules are bonded together and how they are spatially arranged. For example, a water molecule's structure consists of an oxygen atom centrally located, with two hydrogen atoms bonded to it at an angle of approximately 104.5°. A crystal's structure could be described by the arrangement of its atoms, ions, or molecules in a regular, repeating pattern extending in all three spatial dimensions, such as in a sodium chloride (NaCl) crystal, where alternating sodium (Na) and chloride (Cl) ions form a three-dimensional cubic lattice.