Preliminary Chemistry. 'The Chemical Earth'
Chemical Earth
1. The living and non-living components of the Earth contain mixtures
Construct word and balanced formulae equations of chemical reactions as they are encountered
1. Build a word equation
Reactants on left, Products on right
2. Convert word equation into chemical formula for the reactants and products
Using valency rules
3. Balance the equation
Adjust coefficients to get equal numbers of each kind of atom on each side
4. Specify the physical state for each species present
(s) = solid, (l) = liquid, (g) = gas, (aq) = aqueous or dissolved in water
Example
1. Phosphorus + chlorine phosphorus trichloride
2. P + Cl2 PCl3
3. Atoms on either side of the arrow are not balanced
Reactants: P = 1, Cl = 2
Products: P = 1, Cl = 3
Insert coefficients to make balanced
2P + 3Cl2 2PCl3
4. 2P(s) + 3Cl2(g) 2PCl3(l)
Identify the difference between elements, compounds and mixtures in terms of particle theory
Homogenous : Has the same type and distribution of particles throughout and an uniform composition.
E.g. Pure water, sugar, aluminium
Heterogeneous : Having non-uniform composition where there are recognisable small pieces of material
Impure substances: are mixtures
Contaminated with small amounts of one or more other substances
Elements: Pure substances which cannot be decomposed into simpler substances
Compounds: Pure substances which can be decomposed into simpler substances
2 or more elements
E.g. Table salt (sodium chloride), water and elements.
Atoms: The particles that make up elements
An atom is the smallest particle of an element which is still recognisable as that element.
A molecule: Smallest particle of a substance that is capable of separate existence.
Identify that the biosphere, lithosphere, hydrosphere and atmosphere contain examples of mixtures of elements and compounds
The various ‘spheres’ of Earth
Biosphere: The portion of Earth inhabited and used by living matter
Consists of
1. The living and non-living components of the Earth contain mixtures
Construct word and balanced formulae equations of chemical reactions as they are encountered
1. Build a word equation
Reactants on left, Products on right
2. Convert word equation into chemical formula for the reactants and products
Using valency rules
3. Balance the equation
Adjust coefficients to get equal numbers of each kind of atom on each side
4. Specify the physical state for each species present
(s) = solid, (l) = liquid, (g) = gas, (aq) = aqueous or dissolved in water
Example
1. Phosphorus + chlorine phosphorus trichloride
2. P + Cl2 PCl3
3. Atoms on either side of the arrow are not balanced
Reactants: P = 1, Cl = 2
Products: P = 1, Cl = 3
Insert coefficients to make balanced
2P + 3Cl2 2PCl3
4. 2P(s) + 3Cl2(g) 2PCl3(l)
Identify the difference between elements, compounds and mixtures in terms of particle theory
Homogenous : Has the same type and distribution of particles throughout and an uniform composition.
E.g. Pure water, sugar, aluminium
Heterogeneous : Having non-uniform composition where there are recognisable small pieces of material
Impure substances: are mixtures
Contaminated with small amounts of one or more other substances
Elements: Pure substances which cannot be decomposed into simpler substances
Compounds: Pure substances which can be decomposed into simpler substances
2 or more elements
E.g. Table salt (sodium chloride), water and elements.
Atoms: The particles that make up elements
An atom is the smallest particle of an element which is still recognisable as that element.
A molecule: Smallest particle of a substance that is capable of separate existence.
Identify that the biosphere, lithosphere, hydrosphere and atmosphere contain examples of mixtures of elements and compounds
The various ‘spheres’ of Earth
Biosphere: The portion of Earth inhabited and used by living matter
Consists of