Looking around, you can obviously tell that things have different physical properties. A wooden desk will feel hard and holds its shape. Water, on the other hand, feels fluid and has no shape unless put into a container. If you’re entering the world of chemistry, you’re going to want to know the basics of chemical and physical properties.
There will be examples of chemical and physical properties given for several elements and compounds that you should be familiar with. You should also check out a class on the principles of chemistry for more information. If you’re interested in observing chemical and physical properties first hand, you might want to try out the chemistry experiments in this fun article.
General Information About Chemical Properties
Just as we can identify people by certain characteristics, matter can also be identified using different properties. Chemical properties are those properties that change the composition of an element or compound. Examples of chemical properties could include heat caused by combustion, a chemical’s reaction with water, or the pH of an element. Below are some example elements and compounds and their chemical properties.
Also known as water, this particular compound is made up of two elements – oxygen and hydrogen. While both oxygen and hydrogen are more common in gaseous form, water is a fluid form. When frozen, it is known as ice, and when heated, it is known as steam. Water is a chemically active compound, and it’s also polar. Because of its ability to self-ionize, water is a better conductor of electricity than other liquids. Two water molecules together will react to become a hydroxide ion and a hydronium ion.
Another interesting chemical property of water is its fascinating thermal properties. Have you ever noticed that frozen water, ice, will float when placed in water? This is because the compound has become less dense while freezing, which is unusual as most compounds will become more dense. The same can be said for heated water, which expands and becomes more dense. Most substances expand and become less dense when heat is applied.
One of the two elements that make up water, hydrogen has interesting chemical properties as well. Usually seen as a gas, hydrogen is actually made up of diatomic molecules. This means that there are usually two atoms of hydrogen floating about, not just one. When mixed with oxygen, hydrogen can create water or hydrogen peroxide. It is a highly flammable gas. Hydrogen usually becomes water or hydrogen peroxide through combustion. Because of this, hydrogen can actually explode when simply exposed to oxygen.
The second element that makes up water, oxygen is also commonly around us in a gaseous form. This gaseous form is actually two oxygen molecules together. Oxygen is not a flammable gas, but it does support combustion. There is a particular reaction that most substances have when coming into contact with oxygen, and that’s called oxidation.
Commonly known as table sugar (C12H22O11), this compound has many fascinating chemical properties as well. Sugar goes from a crystallized form to a liquid when heated at 320 degrees Fahrenheit. Beyond 338 degrees Fahrenheit, and it takes on new physical properties beyond simply being a liquid. Heat also has the ability to turn sucrose into the crystallized form we’re far more familiar with. It is also a soluble compound, meaning it can dissolve in water.
Made up of two elements, table salt (NaCl) is an ionic compound that resulted from the neutralization of an acid and a base. There are a related number of cations and anions making the end result a compound with a neutral electrical charge. Like sucrose, table salt can dissolve in water or other solvents. How well it dissolves depends on the exact combination of ions versus their interaction with the solvent.
General Information About Physical Properties
An element or compounds’ physical properties are far easier to detect. These properties are things that can be observed without changing the identity of the element or compound. These properties include color, smell, freezing point, boiling point, melting point, opacity, viscosity, and density. Some elements have different physical properties depending on their chemical makeup as some elements can come in different chemical forms. Below are some elements and compounds as well as their physical properties.
Known as the element Fe, iron has a melting point of 2,800 degrees Fahrenheit. It is a silver-gray metal that is highly malleable and ductile. It has great conductivity and can stretch well without breaking. Iron can also be magnetized, and it has a nice luster to it making it nice to look at. Learn more about iron’s role in industrial chemistry with an online course.
Known as the element, C, carbon can have two different colors depending on what form its in. Diamond carbon is transparent and usually has no color. Graphite or coal carbon is black and very dark. Carbon is one of those elements that can have different physical properties depending on what the chemical structure is. Diamond carbon is very strong, one of the hardest substances known to us, but graphite carbon is very soft and is known to be used as the “lead” in lead pencils. If you have a mechanical pencil, just take out one of those graphite sticks so you can see just how different an element can be depending on its chemical makeup.
In its diamond form, carbon has very little electrical conductivity, and it’s considered quite brittle even as strong as it is. Graphite, however, has great electrical conductivity, but it is still brittle. Carbon can’t be made into wires or pounded out into sheets because of its crystalline chemical property. You can learn more about carbon with a class in organic and physical chemistry.
This particular element is usually a gas when found naturally in our environment, but there is also liquid helium. This particular element doesn’t solidify at normal pressure no matter what the temperature is. This element is less dense than every other known gas except hydrogen. It has no color, taste, or scent, and it has a very low viscosity rate. It is an inert element that doesn’t form compounds or react with other elements.
Like helium, chlorine is commonly found as a gas. However, unlike helium, chlorine has a color and a scent. It is greenish-yellow in color, and it has a very disagreeable smell. It is a very dense gas, about two and half times denser than the air around us. It can be dissolved in water and even has an aqueous solution known as chlorine water. This is a mix of chlorine, hydrochloric acid, and hypochlorous acid. Chlorine’s boiling point is -29.29 degrees Fahrenheit, and it melts at -149.8 degrees Fahrenheit.
You’re probably more familiar with potassium when you’re eating a food that has potassium in it like avocados or bananas. However, did you know the solid form of potassium is actually a silvery-white metal with a density lower than water? It also has a melting point of only 145 degrees Fahrenheit, which is very low for a metal.