Chemical and Physical Properties

• Physical properties are characteristics or traits of matter that describe the substance without changing what the substance is.
• State of matter, color, density, pH (acid or base), volume, mass, melting/freezing points, smell, texture, and solubility are examples of physical properties.
• Whether a substance is transparent, translucent or opaque is also a physical property.
• Special descriptions like being metallic, glowing in the dark or being attracted to a magnet can be used as well.
• In fact, ANY description that does not use opinion and does not describe a reaction is a physical property.
• If something changes the appearance of a substance, but not the way the atoms are put together, it is called a physical change and the chemical formula will not change.
• If water freezes into ice, the chemical formula is still H2O.
• If you cut a piece of wood in half, it is still made of wood.
• If you dissolve sugar in water, it is still sugar and water.
• Chemical properties are how a substance will or will not react.
• Examples of chemical properties are combustion (if it will burn), oxidization (rusting), and if the substance will react with another substance.
• If you say that a substance is inert, you are saying that one of its chemical properties is that it will NOT react (like the elements in Column 18 on the Periodic Table!).
• When substances undergo chemical changes, the atoms are rearranged and new bonds are formed or broken.
• This change is called a reaction and the chemical formula of a substance will also change because new substances are formed.
• You can usually tell if a substance changes chemically because the temperature might change by itself without adding heat or ice, a new odor is given off, bubbles form, liquid gets cloudy or color changes.
• Chemical change is when bonds are made or broken and atoms are rearranged.