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A physical property describes an observable change in the characteristics of a substance , but that does not affect its chemical composition. The physical properties of matter can be measured and perceived with the senses (see, hear or smell). Physical properties are temperature, elasticity, melting and boiling points, hardness, brittleness, etc.
Instead, a chemical property can only be observed after a chemical reaction has taken place , that is, after the chemical substance has undergone a transformation, that is, a change of identity. Therefore, chemical properties describe the characteristics that identify substances, that is, that establish their chemical identity. Chemical properties of matter are pH, electrical conductivity, reactivity, ionization potential, etc.
The following are some examples of characteristics that, when varied, show that a chemical change has occurred in a certain matter:
- Uneven color change .
- Change of consistency.
- Brightness change.
- Appearance of bubbles or foam.
- Change of smell
- Temperature change .
- Formation of precipitates (an insoluble solid forms from a liquid solution).
Other examples of physical properties of matter
- Boiling point. It is the temperature of the liquid that makes the vapor pressure equal to the pressure of the gas above it.
- melting point . It is the temperature at which a substance changes from a solid state to a liquid state.
- solubility . The ability of a substance to dissolve in another substance, whether solid, liquid, or gas.
- pressure . The amount of force that is exerted against a given area.
- color . Pigments that are born from the interaction between light and a substance.
- shape . The figure, contours or silhouettes of matter.
- malleability _ The ability of matter to transform without breaking.
- volume . The amount of space that a substance occupies.
Other examples of chemical properties of matter
- flammability _ Ability of a substance to burn and cause fire.
- toxicity . The ability of a substance to cause harm to an organism.
- acidity _ It indicates the amount of acid in a substance.
- reactivity . The rate at which a substance can undergo a chemical reaction.
- Combustion heat . Energy released when a substance burns completely in oxygen.
- Heat capacity of the liquid . Potential of a liquid substance to produce an increase in temperature.
- Gas heat capacity. Necessary heat supplied to a mole of gas to raise its temperature.
- enthalpy of vaporization. Amount of energy required to transform a liquid substance into a gas.
Uses of Chemical Properties
Chemical properties are often used to classify compounds, find useful applications for them, to identify an unknown substance, to separate substances, or to purify substances by separating them from others.
Sources
De Podesta, M. (1996). Understanding the properties of matter .
