Study of matter - flashcards

important key words that seem unfamiliar; complete with must-know notes in same folder :)

Isotope

Atoms of the same element but with different amounts of neutrons.

• have similiar or even identical chemical behavior, but may have differing physical properties (density, radioactivity, etc)

• isotopes can be stable or unstable

• written using isotope notation

Allotrope

Different forms of the same element, where the atoms are arranged in distinct ways

• differing physical and chemical properties (ie, conductivity)

• carbon: diamond, graphite, graphene, fullerene

Molecule

2 or more atoms that are held together by (most commonly) covalent bonds

• sizes range from diatomic molecules to complex macromolecules

Compound

Substance composed of two or more different elements that are chemically bonded together

• ionic, covalent or metallic bonds

• have fixed ratios depending on the atoms

• need chemical methods to break the bonds

Mixture

Combination of two or more substances, where each substance retains its own chemical properties

• no chemical bonds between the substances, meaning that they can be separated by physical means

Homogeneous mixtures

Mixtures uniform in composition and appearance throughout

• solution

• alloy

• gaseous mixtures

• colloids

Solution

Homogeneous mixture where a solute is dissolved in a solvent

• can be separated by physical processes like evaporation or filtration

Alloy

Homogeneous mixture of metals

Gaseous mixture

Homogeneous mixture of gas

• distribute uniformly

• most commonly separated by distillation or fractional distillation, chromatography and absorption

Colloids

Homogeneous or heterogeneous mixtures depending how well the other substance is distributed throughout the other one.

• for example whipped cream has two distinct phases (gas, liquid) which makes it heterogeneous, but milk is also a colloid, but homogeneous since the fat that it contains is well uniformly distributed throughout

• for homogeneous colloids, ways of separation include

  • ultrafiltration

  • centrifugation

  • electrophoresis (separated using an electric field)

• for heterogeneous colloids, ways of separation include

  • filtration and sieving

  • settling and decantation

  • centrifugation

Suspensions

Heterogeneous mixture where solid particles are dispersed throughout a liquid or gas, undissolved

• can be separated by means of:

  • filtration

  • decantation

  • centrifugation

  • evaporation

  • magnetism

Heterogeneous mixtures

Mixtures not uniform and as such, the individual components can be seen and distinguished from one another

• suspensions

• colloids

• emulsions

• mechanical mixtures

Emulsion

Heterogeneous mixture that is a subtype of colloids, where the dispersed phase and continuous phase are both liquids

• may be so unstable that separates over time

• can be separated by means of

  • centrifugation

  • decantation

  • heating breaks the emulsion

  • addition of emulsifying agent, destabilizing the emulsion

  • filtration in some cases

Mechanical mixtures

Heterogeneous mixtures where the components are physically distinct and can be easily separated by filtration

Distillation

Way of separating homogeneous mixtures by utilizing differences in the boiling points of the components

Evaporation

Way of separating homogeneous mixtures by utilizing difference in boiling points or the volatility (vaporization ability)

Fractional distillation

Way of separating homogeneous mixtures with close but not the same boiling points, may include multiple steps

Chromatography

Way of separating homogeneous or heterogeneous mixtures based on their different ways of moving from stationary to mobile phases (move at different rates through a tube)

Ultrafiltration

Way of separating homogeneous mixtures where semi-permeable membrane is used to separate particles based on size (water purification)

Centrifugation

Using centrifugal force to separate components of a homogeneous or heterogeneous mixture based on density (spinning at high speeds to separate)

Filtration, sieving

Way of separating heterogeneous mixtures by utilizing differences in particle size

Settling and decantation

Way of separating heterogeneous mixtures by the settling of particles over time based on density

Magnetic seperation

Used to separate heterogeneous mixtures’ components when one is magnetic

Crystalline solid

Solid substance with a regular repeating structure (ie, diamond, NaCl)

Amorphous solid

Solid substance with no organized pattern in its lattice (glass)

Changes of state where energy is absorbed

Melting

Vaporization

Sublimation

Changes of state where energy is released

Freezing

Condensation

Deposition