5.1 how are elements, compounds and mixtures different Flashcards
what are elements made out of
only one element
how are elements formed
mostly naturally occurring
elements have __ melting and boiling points
fixed
what are compounds made out of
two or more elements that have been chemically combined
how are compounds formed
from a chemical reaction
what are the properties of compounds
has different properties form its constituent elements
compounds melting and boiling points are __
fixed
what is a mixture made out of
two or more elements and/ or compounds that are not chemically combined
how are mixtures formed
usually from physical mixing
ratio or the constituents in a mixture
no fixed rafio
properties of a mixture
usually has similar properties to its constituent substances
mixtures melt and boil ___
over a range of temperatures
difference between elements and compounds
an element is a pure substance that cannot be broken down into 2 or more simpler substances by chemical methods
a dkmlluns is a pure substance containing 2 or more elements that are chemically combined in a fixed ratio
elements can appear as:
- atoms, if they are nit chemically bonded to each other
- molecules, if they are covalently bonded
- a lattice or positive ions with a ‘sea of delocalised electrons’
elements are chemically bonded together to form
with covalent or ionic compounds
what chemical methods can be used to separate compounds into their constituent elements
- thermal decomposition
- electrolysis
thermal decomposition
exposing the compound to strong heat
electrolysis
passing electric current through the compound
difference bereeen compounds and mixtures
a compound has a fixed proportions of different kinds of atoms it is made up of
mixtures do not have substances in a fixed ratio
what are some physical methods to separate mixtures into their constituents
filtration
chromatography
distillation
