Definitions P2 Flashcards
Matter
made up of particles whose properties determine the observable characteristics of matter and its reactivity.
Mixture
a combination of two or more substances, where these substances are not bonded (or joined) to each other and no chemical reaction occurs between the substances.
Heterogeneous
Consists of two or more substances, is a non-uniform composition and the different components can be seen.
Homogeneous
One that is a uniform composition where the different components cannot be seen. All components are in the same phase.
Pure Substances
cannot be separated into simpler components
Elements
a substance that cannot be broken down into other substances through chemical means. On the periodic table. E.g.Hydrogen
Compound
a substance made up of two or more different elements that are joined together in a fixed ratio. E.g. NaCl, FeS
Brittle
Hard but likely to break easily
Strength
the force it can resist before it deforms
Malleable
ability to be hammered or pressed into a shape without breaking or cracking.
Ductile
ability to be stretched into a wire
Density
the mass per unit volume of a substance / how close together (dense) the particles in a material is packed (mass ÷ volume)
magnetic properties
how easily it is attracted by magnets/magnetic objects
Magnetism
a force that certain kinds of objects (magnetic objects) can exert on each other without physically touching. Surrounded by a magnetic field that gets weaker further from the objects.
Thermal Conductivity
the extent to which a substance conducts heat
Thermal Conductor
a material that allows heat to pass through easily
Electrical Conductivity
the extent to which a material conducts electricity
Electrical Conductor
a material that allows an electrical current flow of charge to pass through it. E.g. copper wire
Electrical semi-conductor
a substance that can conduct electricity under some conditions, but not other, making a good medium for the control of electrical current.
Electrical Insulator
a material that prevents the flow of charge/electrical current to pass through it. Non conductivity material that doesn’t carry charge. E.g. wood
Diffusion
The movement of particles from an area of higher concentration to an area of lower concentration
Brownian Motion
the random movement of microscopic particles suspended in a liquid or gas, caused by collisions between these particles and the particles of the liquid or gas.
Melting/boiling point
how much heat has to be applied to change the material from a solid to a liquid or liquid to gas.
Boiling Point
the temperature of which a liquid’s vapour pressure equals the external (atmospheric) pressure.
Melting Point
the temperature at which a solid, given sufficient heat, becomes a liquid/change phase, called melting
Freezing
the temperature at which a liquid changes its phase to become a solid, called freezing
Evaporation
the change of a liquid to vapour at any temperature below the boiling point. It takes place at the surface of a liquid, where molecules have the highest kinetic energy that are able to escape.
Condensation
the process during which a gas or vapour changes to a liquid/either by cooling or being subjected to increased pressure.
Sublimation
the process during which a solid changes directly to a gas without passing through an immediate liquid phase.
Melting
the process during which a solid changes to a liquid
Freezing
the process during which a liquid changes to a solid
Kinetic theory of matter (it’s long)
it attempts to explain the behaviour of matter in different phases. It says that all matter is composed of particles which have a certain amount of energy which allows them to move at different speeds depending on the temperature (energy). There are spaces between particles and also attractive forces between particles when they come close together.
Cation
a positive ion
Anion
a negative ion
Oxides
a compound with oxygen
Atomic number
(Z) The number of protons in an atom of an element.
Atomic mass
(A) The number of protons and neutrons in the nucleus of an atom.
Isotope
The isotope of an element is made up of atoms which have the same number of protons as the atoms in the original element, but a different number of neutrons.
Orbital
Defines the space in which an electron is most likely to be found.
Electron configuration
The arrangement of electrons in an atom, molecule or other physical structure around the atomic nucleus.
Valence electrons
The electrons in the outermost energy level.
Core electrons
The electrons in an atom that are not valence electrons.
A group
A column on the periodic table containing elements with similar properties.
A period
A row on the periodic table.
Atomic radius
A measure of the size of the atom.
The first ionisation energy
The energy needed to remove 1 electron from an atom in the gas phase.
Electronegativity
The tendency of atoms to attract electrons.
Periodicity
It refers to the gradual change in physical and chemical properties of elements when moving from left to right.
Dispersion
is a process whereby the particles of one substance are scattered all through another substance.
A solution
