Matter and Its Properties

Chemistry

Study of matter and the changes it undergoes.

Matter

Anything that occupies space and has mass.

Kinetic Molecular Theory

All matter consists of extremely minute particles that are in constant motion.

States of Matter

Solid, Liquid, Gas

Solid

• Definite shape and volume

• Particles are tightly packed together

• Incompressible

• High density

Liquid

• No definite shape but has definite volume

• Particles are close but not as close as those in solids

• Almost incompressible

• Medium densithy

Gas

• Takes the shape of its container

• Particles are far away from each other

• Highly compressible

• Low density

Physical Properties

Properties that can be observed and measured without changing the composition of a substance.

Mass

Amount of matter in an object.

Volume

Space occupied by an object.

Density

Mass per unit volume.

State of Matter

Physical form (solid, liquid, gas)

Melting Point

Temperature at which a solid turns into a liquid

Boiling Point

Temperature at which a liquid turns into a gas.

Solubility

Ability of a substance to dissolve in a solvent.

Hardness

Resistance to deformation

Color

Visual perception based on the spectrum of light emitted.

Odor

The smell of the substance

Malleability

Ability to be hammered or rolled into thin sheets.

Ductility

Ability to be drawn into wires.

Luster

How shiny or reflective a surface is

Opacity

Degree to which a substance is opaque or transparent.

Viscosity

Measure of a fluid’s resistance to flow.

Chemical Properties

Properties that describe the potential of a substance to undergo a chemical change or reaction by virtue of its composition

Reactivity

Tendency of a substance to engage in chemical reactions

Flammability

Ability of a substance to burn in the presence of oxygen

Toxicity

Degree to which a substance can cause harm to living organisms

Corrosiveness

Aility of a substance to damage or destroy other materials

Radioactivity

Spontaneous emission of particles or radiation from an unstable nucleus

Stability

Tendency of substance to remain unchanged chemically

Intensive Property

Independent on the amount of substance being measured.

Extensive Property

Dependent on the amount of substance being measured.

Physical Change

Affects a substance’s physical properties without changing its chemical composition

Chemical Change

Results in the formation of new substances with different chemical properties and compositions from the original substance

Pure Substance

Type of matter with a fixed composition and distinct properties.

Elements

• Simplest form of pure substance

• Composed of one type of atom

Compounds

Substances that are composed of two or more elements held together by chemical bonds

Mixture

Physical combination of two or more substances that do not chemically react

Homogenous Mixture

Mixture with a uniform composition

Heterogenous Mixture

Mixture that does not have a uniform composition

Suspension

Type of heterogenous mixture where particles are large enough to settle out over time due to gravity

Colloid

Mixture where dispersed particles are intermediate in size and do not settle out over time and remain evenly distributed throughout the dispersing medium.

Decantation

• Process of separating two substances with differences in density. Solid sediment (residue) will settle at the bottom of the container allowing separation of the supernatant liquid.

• Liquids of different densities will form two layers allowing separation.

Filtration

• Separates an insoluble solid from a liquid

• Example is sand and water

• Used in water treatment plants, where water from the river is filtered to remove solid particles

Evaporation

• Process by which a liquid changes from liquid state to a vapor or gas state

• Good for separating a mixture of a soluble solid and a solvent

• Involves heating the solution until the solvent evaporates leaving behind the solid residue

Distillation

• Process of separating mixtures of liquids with different boiling points or volatilities

• The liquid left in the flask is called the residue. The liquid collected at the collection flask or beaker is called the distillate.

Sublimation

Used for the separation of a solid-solid mixture where one of the components sublimes upon heating, leaving behind the other components that are non-sublimable

Chromatography

Process for separating components of a mixture. The mixture is dissolved in a substance called the mobile phase, which carries it through a second substance called the stationary phase.

Measurement

Consists of two essential parts, a number and a scale (unit)

Le System International d’Unites (The International System of Units

Modified version of the metric system used to record and report measurements

Fundamental Units

Basic units defined by the International System of Units (SI) from which all other units are derived

Derived Units

Formed by combining fundamental units, often involving multiplication or division. Measures more complex quantities.

Accuracy

Refers to how close each measurement is to the actual value.

Precision

Degree of agreement among several measurements of the same quantity.

Significant Figures

Numbers in which the certain digits and the first uncertain digit are recorded

When are numbers considered significant?

• All nonzero digits (1-9)

• Zeroes between nonzero digits

• Zeroes to the right of a nonzero number, and to the right of a decimal place

When are zeroes not significant?

• Zeroes that occur before the first nonzero digit

• Trailing zeroes wherein there is no decimal point before or after these zeroes

Scientific Notation

Used to represent very large or very small numbers as powers of 10.

Length

Measurement of distance from one point to another

Volume

The quantity of three-dimensional space enclosed by a closed surface, for example, the space that a substance or shape occupies.

Temperature

The measure of how hot or cold a material is

Density

Ratio of the mass of an object to its volume

Dimensional Analysis

General problem-solving approach that uses the dimensions or units of each value to guide through calculations.

Formula for Density

Density = Mass / Volume