2.1 The Water Cycle Flashcards
atom
the smallest particle of a substance that can take part in a chemical reaction
molecule
a group of atoms held together by sharing electrons between atoms in the molecule
particle theory
a theory which describes the bulk properties of the different states of matter in terms of the movement of particles ( atoms or molecules )- the theory explains what happens during changes in physical state
kinetic energy
the energy possessed by objects or particles due to movement
physical state
solid,liquid and gases are the three states of matter in which any substance can exist, depending on the conditions of temperature and pressure
melting point
the temperature at which a solid turns into a liquid; it has the same value as the freezing point
latent heat energy
energy absorbed or released by a substance during a change in its physical state
boiling point
the temperature at which a liquid boils
water vapour
gaseous water in the air that has evaporated
water cycle
the cycle of processes by which water circulates between the Earth’s oceans, atmosphere,and land , it involves precipitation,drainage and run off into streams and rivers,and return to the atmosphere by evaporation
atmosphere
layer of gases surrounding the surface of the earth
freeze
the change of a liquid into a solid; during this process heat is given out to the surroundings
soluble
the description of a substance that dissolves in a particular solvent
diffusion
the random movement of particles from an area of higher concentration to an area of lower concentration ( down a concentration gradient); it is a passive process, not requiring the input of energy
surface area
the outer part or exposed area of a material
