The substitution reactions are the reactions which depend on the activity of metals, where the element which is more active substitutes (replaces) the less active one in another compound, The activity of metals can...
The salts The salts are ionic compounds that result from the the neutralization reaction of an acid and a base , they are composed due to the combination of a positive ion ( or...
Nitrogen gas properties Nitrogen gas ( N2 ) is mainly found in the atmosphere , it is also found in the Earth’s crust in the form of nitrates , it is found in the...
The electric conductivity The substances can be classified according to the electric conductivity into good conductors of electricity and bad conductors of electricity , The electrical conductivity is the ability of a material to...
Hardness of materials Some solid substances are soft at room temperature such as the rubber , and some solid substances need heat to become soft and easy to be shaped such as the metals...
The melting point The matter exists in three states which are solid , liquid and gas , and the matter can change from one state to another by heating , The change of matter...
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