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
Give and example of a homogeneous mixture
solutions
What are some examples of heterogeneous mixtures?
suspensions and colloids
What is a solution?
a homogeneous mixture of 2 or more substances
has a solute and solvent
What are characteristics of solutions?
- particles cannot be seen with the naked eye
- light can pass thrugh /transparent
cannot be seperated by filtration
Examples of solutions
salt water
rum
vinegar
soda
air
syrup
honey
What are suspensions?
a heterogeneous mixture in which visible particles of a substance is dispersed in another substance
characteristics of suspension
particles are visible to the naked eye
can be seperated using filtration
may appear opague
particles settle on standing
What are colloids?
heterogeneous mixtures that have particles smaller than a suspension but larger than a solution.
examples of suspensions
dust in air
mud in water
sand in water
oil in water
what are some characteristics of colloids?
particles are not visible to the naked eye
particles do not settle and cannot be seperated physically
translucent
examples of colloids
emulsion
gels
smoke
fog
cloud
foam
