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a) Physical changes– they are normally reversible and no new substances formed. Examples are;
(i) Change of state such as melting and vaporization
(ii) Thermal expansion due to heating
(iii) Dissolving solids in liquids
(iv) Magnetizing
(v) Charging electrically
b) Chemical changes– they are irreversible and new substances are formed Examples are;
(i) Changes caused by burning
(ii) Changes occurring in some chemicals due to heating e.g. mercuric oxide
(iii) The reactions resulting from mixing chemicals to form other substances.
c) Nuclear changes– these are changes occurring in nuclear substances which give off some particles i.e. Uranium and Radium. As this happens they change into other substances.
raphael answered the question on October 9, 2018 at 18:37
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