Elements cannot be decomposed into simpler substances. Compounds are 2 or more elements chemically combined (sodium chloride)
Mixtures (physical combination of 2 or more pure substances)
Mechanical mixtures: where you can see all components (vinegar oil. Solutions: are blended, 1 phase.
absorbs energy, bonds are broken
releases energy, synthesis reaction (exo-=exit)
property you can observe without changing 1 kind of mater into another. COLOUR TASTE TEXTURE DENSITY MALLEBILITY VISCOSITY
property you can observe when 1 kind of matter is converted into another kind of matter.
changes that do not affect the chemical composition, only changes the physical appearance. CHANGES OF STATE CHANGES OF FORM. Melting, solidification, evaporates, condensates, sublimation (solid to gas or gas to solid) ALL REVERSIBLE BY ADDING OR REMOVING HEAT
colour change, heat or light is given off, a gas was formed, precipitate forms, odour, IRREVERSIBLE