Structure 1.1 Flashcards
Element
D: Elements are the primary constituents of matter, which cannot be chemically broken down into simpler substances.
S: Cannot be separated (from itself) by chemical or physical processes.
C: It has definite and unform chemical composition. It is composed of one kind of atoms.
C: Determined by its location in the periodic table, esp group.
M: Fixed and sharp
Compounds
D: Compounds consist of atoms of different elements chemically bonded together in a fixed ratio.
S: Can be decomposed into its constituent elements by chemical processes.
C: It has definite and uniform chemical composition. It is composed of 2 or more kinds of atoms in a fixed ratio.
C: The chemical properties are different from that of its constituent elements.
M” Fixed and sharp
Mixtures
D: Mixtures contain more than 1 element or compounds
1. in no fixed ratio
2. not chemically bonded
3. can be separated by physical methods.
S: Can be separated by physical means.
C: It does not have a definite and uniform chemical composition. It is composed of atoms, molecules or ions of different elements and/or compounds in variable proportions.
C: It shows all the chemical properties of its constituent substances.
M: Melts and boils over a range of temperatures.
Homogenous mixtures
D:
1. Mixtures with uniform composition & properties through, also known as solutions.
2. Their particles are evenly distributed.
Heterogenous mixtures
D:
1. Mixtures with non-uniform & varying properties.
2. Their particles are not evenly distributed.
Filtration
Audience: heterogenous mixtures
Description: mixture is poured through a paper filter or other porous material.
Removed: liquid
Left: Solid
Dissolution
Audience: heterogenous mixture (solid+solid)
Description: mixture is added to water or organic solvent.
Removed: Soluble substance(s)
Left: Insoluble substance(s)
Crystallisation
Audience: homogenous mixtures
Description:
1. mixture is dissolved in hot water or organic solvent till saturation
2. solution is left to cool
3. Crystals formed are isolated through filtration
Removed: more soluble substance(s)
Left: less soluble substance(s)
Distillation
Audience: homogenous mixture
Description: mixture is heated up until one or more of its components reaches boiling point, boils and vapourises.
Removed: more volatile liquid(s)
Left: solid(s) / non-volatile liquids.
Paper chromoatography
Audience: homogenous mixture
Description:
1. mixture is placed on a piece of paper.
2. one side of the paper is submerged in water or a solvent.
3. components move along the paper.
Removed: more soluble component(s) that move(s) faster
Left: less soluble component(s) that move(s) slower or stay(s) in place.
Reflux
*NOT A SEP TECH
Purpose: Heat reaction mixtures while minimising the loss of volatile substances during continuous heating.
Description: A condenser is placed above the reaction flask, so that any vapours rising from the reaction mixture condense and drip back down into the flask instead of escaping.
