Structure 1.1 Introduction to the particulate nature of matter Flashcards
What is matter?
Any substance that has mass and volume. Composed of atoms/ions/molecules/etc.
What is an element?
pure substance made out of atoms with the same number of protons, and cannot be chemically broken into a simpler substance
What is a compound?
Pure substance composed of two or more atoms of different elements chemically bonded in a fixed ratio
What is a pure substance?
Form of matter with consistent chemical composition, fixed properties and cannot be separated into simpler substances by physical means
What is a mixture?
More than one element or compound in no fixed ratio, which is not chemically bonded and can be separated by physical methods into pure substances (mixed but not chemically combined). Can have variable properties depending on composition
Heterogenous mixture
Mixture that does not have a uniform composition and properties throughout (e.g. rocky road)
Homogeneous mixture
mixture with a uniform composition and properties (e.g. steel, air, any aqueous solution)
Physical change
reversible change in the physical properties of a substance in which no new substances are formed
Solute
solid/liquid/gas that dissolves in a liquid solvent to form a solution of solvated ions or molecules
Solvent
A usually liquid substance that is capable of dissolving a solute
Solution
Liquid mixture in which the solute is uniformly distributed within the solvent i.e. homogenous
Solvated
(of a solute) surrounded by the solvent’s molecules
Hydrated
ions solvated with water (surrounded by water molecules)
Anhydrous
Containing no water/opposite of hydrated
Identify the solvent, solution and solute with sodium chloride dissolving in water
Solvent: water
Solute: sodium chloride
Solution: aqeuous mixture of sodium and chloride ions solvated with water
Soluble
dissolves readily in a solvent, particularly water
Saturated solution
a solution where no more solute can dissolve at a particular temperature
Solubility (of a substance)
amount of solute needed to form a saturated (maxed out) solution
What is the solubility of a substance expressed as?
Often expressed as the mass that will dissolve into 100cm3 at a particular temperature
Miscible
when liquids mix together, they form one uniform layer of homogeneous mixture
Immiscible
when liquids mix together, they do not mix and instead form two separate layers
What are the separation techniques?
Filtration
Evaporation
Recrystallisation
Distillation
Paper chromatography
What is filtration?
physical separation process that separates solid matter and fluid by the use of a filter medium that permits only the fluid to pass through
What does filtration work on?
heterogeneous, insoluble solid + liquid
What is the difference in physical property that allows separation in filtration?
Solubility
What is Evaporation?
type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. This technique involves heating the solution, so that the liquid evaporates. This leaves the solid behind, separating the two substances
Mixture type for evaporation?
soluble solid and a liquid, homogenous
What is the difference in physical property that allows separation for evaporation?
Volatility
What is recrytillisation for?
Purify organic compounds