Pure substances, Mixtures and Seperations Flashcards
What can matter be classified in?
pure substances and mixtures.
What are the 2 types of pure substances
elements and compounds
What are two types of mixtures?
homogeneous and heterogeneous
What are pure substances?
A pure substance is composed of a single material only
What are the characteristics of pure substances?
- Compositions are fixed
- Properties are fixed and constant
- They cannot be seperated by any physical means
What are elements?
Elements are pure substances that cannot be broken down into simpler substances by any physical or chemical means
What are elements composed of?
atoms
What can elements be classified as?
metals and non metals
What are some physical properties of metals and non metals?
Boiling and melting points- metals higher than nonmetals
state at room temperature- metals- solid (except for mercury), non mentals (can be solid liquid or gas)
density- metals (high), non metals(low)
appearance- metals(shiny), non mentals(dull)
electrical and thermal conductivity- metals (good), non metals (poor except for graphite)
What is a compound?
a pure substance formed from joining two or more elements that are chemically bonded together in fixed proportions.
What is a mixture?
A combination of two or more substances that are combined physically in variable proportions.
What are the two types of mixtures?
homogeneous and heterogeneous
What are the characteristics of mixtures?
- Compistion can vary
- Properties are various
- can be seperated by phyical means
What are homogeneous mixtures?
they are uniform
cannot tell the different components
What are heterogeneous mixtures?
they are non uniform
can tell the different components
