elements compounds mixtures Flashcards
define elements (3)
substances that cannot be further split into anything simpler by chemical means
contains only one type of atom shown in diagram as one size or colour
all elements listed on periodic table into metals and non metals
define metals (6)
usually solid or occasionally liquid
shiny appearance
usually high melting point
usually high boiling point
usually high density
good thermal and electrical conductivity
define non metals (6)
solid liquid gas
dull appearance
usually low melting point
usually low boiling point
usually low density
very poor thermal and electrical conductivity
define compounds
formed when two or more elements chemically combine always in fixed proportions
give 7 examples of compounds
hydrogen fluoride HF
magnesium fluoride MgF2
carbon dioxide CO2
methane ch4
water h20
ammonia nh3
sodium chloride nacl
define mixtures
various substances mixed together and no chemical reaction occurs made up of elements and/or compounds in any proportion
give 3 examples of mixtures
elements - nitrogen and oxygen
compounds - carbon dioxide and water
elements and compound - carbon dioxide and nitrogen
state differences between mixtures and compounds
single substance
composition always same
new substance formed involving chemical change
properties very different to those of compound elements
only separated by one or more chemical reactions
contains two/more substance
varied composition
no chemical change takes place when formed
properties those of individual elements/compounds
separated quite easily by physical means
define heterogeneous
parts of mixture noticeably different from one another not uniformly distributed throughout
sand salsa
define homogenous
substances so evenly distributed so difficult to distinguished one substance in the mixture from another and uniform in composition
swimming pool water stainless steel fork
