It embodies all the essential components of present day definition, i.e. site, nature, aggravating and relieving factors and referral. According to him angina is chest pain which is precordial, temporary, exertional, emotional, burning like and relieved by rest. He also linked this kind of pain to obesity (medoroga).
Pure substances are defined as substances that are made of only one type of atom or molecule. The purity of a substance is the measure of the extent to which a given substance is pure. The physical properties of a pure substance include well-defined melting and boiling points. The purity of a substance also impacts the chemical properties of a substance by reducing the chances of unexpected products being formed if impurities are present within the substance.
A substance is matter which has a specific composition and specific properties. Every pure element is a substance. Every pure compound is a substance. Examples of substances: Iron is an element and hence is also a substance. Methane is a compound and hence is also a substance.Examples of non-substances: Salt water is not a substance.It is a mixture of two substances-sodium chloride and water. Its composition and therefore its properties are not fixed.Gasoline is not a substance.xamples of non-substances: Salt water is not a substance. It is a mixture of two substances-sodium chloride and water. Its composition and therefore its properties are not fixed. Gasoline is not a substance.