1. The living and nonliving components of the Earth contain mixtures
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Construct word and balanced formulae equations of chemical reactions as they are encountered Reactants → products
Chemical reaction: the way atoms are joined changes, atoms are not created nor destroyed, but are rearranged
Indicators:
emission of light or heat, odour
formation of a gas
formation of a precipitate
colour change
change in state aqueous = dissolved in water, an aqueous solution
Diatomic elements (ogens or ines)
H2, N2, O2, F2, Cl2, Br2 (liquid), I2 (solid), At2
Common valencies:
NH4 (Ammonium) 1+
Zn 2+
NO3 1
OH 1
CO3 2
SO4 2
PO4 (phosphate) 3
Combustion reaction: compound + oxidant → heat + product hydrocarbon + O2 → CO2 + H2O
Ionic equation: Metal + Non metal
Law of conservation of Mass:
In all chemical reactions, mass is conserved. The total mass of all the reactants equals the total mass of all the products.
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identify the difference between elements, compounds and mixtures in terms of particle theory
All matter consists of many very small particles which are constantly moving or in a continual state of motion.
Use of the general term ‘particle’ means the precise nature of the particle does not have to be specified. The particles may be ions, atoms or molecules.
The particle theory of matter states:
● all matter is made up of tiny particles
● these particles are in a continual state of motion
● matter is held together by very strong electric forces
● the empty spaces between the particles of matter in gases are very large compared to the particles themselves
● the particles of one substance are different from the particles of another substance
● the degree to which the particles move is determined by the amount of energy they have and their relationship to other particles
Element:
● consists of only one type of atom
● cannot be broken down into a simpler type of matter by either