Chemistry Flashcards
Solutions and Mixtures
Element
Contains one type of atom, which may occur individually or bonded to form molecules
Compound
Two or more elements that are chemically bonded together (DO NOT APPEAR IN PERIODIC TABLE)
Mixture
Contains at least two different substances (elements and/or compounds) NOT bonded chemically
Are mixtures pure or impure?
Impure
Are compounds and elements pure or impure?
Pure
What is easier to separate: mixtures or elements that make up a compound?
Mixtures
Physical change
Rearranging particles, but individual particles are not changed in any way
Are physical changes reversible?
Yes
What is an example of a physical change?
Separating mixtures
Solute
The substance being dissolved
Solvent
The liquid it’s being dissolved in
Miscible liquids
Liquids that mix together (i.e water and squash)
Immiscible liquids
Liquids that don’t mix together (i.e water and oil)
What is a separating funnel used for?
Separate immiscible liquids by opening the tap to remove the denser liquid.
Distillation
Process for separating two or more miscible liquids, making use of their different boiling points.
What happens in the process of distillation?
When the first liquid boils (the one with
the lower boiling point), its vapour
passes upwards, into the condenser,
where it is cooled, condensing it to
form a liquid which is collected in the
beaker.
Does the liquid with the higher boiling point or the liquid with the lower boiling point stay in the flask?
Higher boiling point
What happens if more than 2 miscible liquids are mixed together?
What process is used to separate/identify the liquids?
A thermometer may be used to identify each liquid as it boils.
What can distillation be used for?
Purification (impurities stay in the flask) or increasing the concentration in a liquid
What happens if the two liquids have very similar boiling points?
Slightly different apparatus is used for fractional distillation. A longer column is used for more space for separating the two liquids.
What is fractional distillation useful for?
Separating crude oil from chemicals so that they can be used separately
