Matter (CHEM111)

  • Chemistry - (1) the field of study concerned with the characteristics, composition, and transfer of matter.

  • Matter - (1) includes all things, both living and non-living. (2) it's fundamental nature that includes the physical state, properties, and the changes it undergoes.

  • Physical state - has three states of matter which is solid, liquid, and gas.

  • Solid - characterized by a definite shape and a definite volume.

  • Liquid - characterized by an indefinite shape and a define volume.

  • Gas - characterized by an indefinite shape and volume.

  • Property - distinguishing characteristic of substance that is used in its identification and description (it has two type, physical and chemical property)

  • Physical property - characteristics that can be observed without changing the basic identity of the substance (ex. color, odor, physical state, melting/boiling point, hardness)

  • Chemical property - describes this way the substance undergoes or resists change to form a new substance

  • Physical changes - substance changes its physical appearance but not chemical composition

  • Chemical changes - substance undergoes a change in chemical composition. it always involve conversion of the material under consideration into one or more new substances.

  • Matter - can also be classified in terms of its chemical composition as a pure substance or as a mixture

  • Pure substance - a single kind of matter that cannot be separated into other kinds of matter by any physical means (ex. pure water, pure sugar)

  • Mixture - (1) physical combination of two or more pure substances in which each substance retain its own chemical identity (ex. mixture of rocks salt and ordinary sand). (2) any mixture is that its components can be separated using physical means

  • Mixtures - are sub classified as heterogeneous or homogeneous

  • Heterogeneous mixture - a mixture that contains visible different phases (parts), each of which has different property.

  • Homogeneous mixture - contains only one visible distinct phase (part), which has a uniform properties throughout (ex. sugar water mixture)

  • Element - pure substance that cannot be broken down into simpler pure substance by chemical means (ex. gold, silver, copper, hydrogen)

  • Compound - pure substance that can broken down into two or more simpler pure substances by chemical means (ex. water (h2o) can be broken down into the elements hydrogen and oxygen)

  • Substance can be combined either physically or chemically.

  • Physical combination - produces a mixture

  • Chemical combination - produces a compound substance in which combining entities are bound together

  • No such binding occurs during physical combination

  • Elements - (1) discovery and isolation of the 117 known elements, the building blocks for all matter, have taken place over a period of several centuries. (2) most of the discoveries have occured since 1700, the 1800s being the most active period. (3) each element has unique name; some bear geographical names like (germanium, francium and polonium), some are named for the planets (mercury, uranium, neptunium), some reflect specific properties of the element or of the compounds containing it.

  • Chemical symbol - one or two letter designation for an element derived from the element's name

  • Atom - (1) the smallest particle of an element that can exist and still have the properties of the element. (2) sample of any element composed of atoms of a single type, those of that element are contrast, a compound must have two or more types of atoms present because by. definition at least two elements must be present. (3) free atoms are rarely encountered in nature. (4) almost always found together in aggregates or clusters.

  • Molecule - a group of two or more atoms that functions unit because the atoms are tightly bound together

  • Diatomic molecule - a molecule that contains two atoms

  • Triatomic molecule - contains three atoms

  • The atoms present may all be of the same kind, or two or more kinds may be present

  • Homoatomic molecule - a molecule in which all atoms present are of the same kind. substance containing homoatomic molecules are elements (ex. hydrogen H2, oxygen O2, nitrogen N2, and chlorine Cl2)

  • Heteratomic molecule - molecule in which two or more kinds of atoms are present. Substances containing heteratomic molecules are compounds (ex. water H2O)

  • Compounds - molecules made of atoms from different elements

  • Molecules - atoms connected by chemical bond

  • All compounds are molecules, but not all molecules are compounds

  • H2 is a molecule, but not a compound (only H is present)

  • H2O is both molecule and a compound (H and O are present)

  • Chemical formula - notation made up of the chemical symbols of the elements present in a compound and numerical subscripts (located to rhe right of each chemical symbol) that indicates the number of atoms of each element present in molecule of the compound