Chemical substance

A chemical substance is a form of matter with a consistent chemical composition and unique properties. These substances are the fundamental units that make up our physical world, from the air we breathe to the food we eat.

Pure Substances Have Constant Composition

Chemical substances come in two main flavors: elements and compounds. Elements, like oxygen or gold, consist of only one type of atom. Compounds, such as water (H2O) or table salt (NaCl), are made up of different elements bonded together in fixed ratios. This constant composition is what sets chemical substances apart from mixtures.

Physical States Don’t Change Chemical Identity

One cool thing about chemical substances is that they can exist in different physical states without changing their chemical makeup. Water, for example, can be a solid (ice), liquid, or gas (steam), but it’s always H2O. The state just depends on temperature and pressure.

Chemical Reactions Create New Substances

When chemical substances interact, they can form new substances through chemical reactions. This is how we get everything from the rust on your bike to the plastic in your phone. Some substances, though, are inert – they don’t react easily with other chemicals.

Pure Water: The Universal Example

Let’s take a closer look at water, the poster child for chemical substances. Every water molecule has two hydrogen atoms bonded to one oxygen atom. This 2:1 ratio never changes, whether you’re looking at a raindrop or an ocean. Pure water always boils at 100°C (212°F) at sea level – that’s one of its characteristic properties.

From Diamonds to Sugar: Diverse Substances

Chemical substances are incredibly diverse. Here are a few examples:

• Diamond: A form of pure carbon, prized for its hardness and sparkle.
• Table salt (NaCl): An ionic compound that makes our food tasty.
• Sugar (C12H22O11): An organic compound that sweetens our lives.

Each of these substances has its own unique set of properties that make it useful (or beautiful) in different ways.

Chemical substances are the Lego bricks of our material world. Understanding them helps us make sense of everything from cooking to climate change. So next time you sip a glass of water or sprinkle salt on your food, remember – you’re interacting with some of the most fundamental building blocks of our universe.

Citations:

1. https://en.wikipedia.org/wiki/Chemical_substance

Chemical_substance (Wikipedia)

"Chemical" redirects here. For other uses, see Chemical (disambiguation).

A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. If a mixture is separated to isolate one chemical substance to a desired degree, the resulting substance is said to be chemically pure.

Chemical substances can exist in several different physical states or phases (e.g. solids, liquids, gases, or plasma) without changing their chemical composition. Substances transition between these phases of matter in response to changes in temperature or pressure. Some chemical substances can be combined or converted into new substances by means of chemical reactions. Chemicals that do not possess this ability are said to be inert.

Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a single oxygen atom (i.e. H₂O). The atomic ratio of hydrogen to oxygen is always 2:1 in every molecule of water. Pure water will tend to boil near 100 °C (212 °F), an example of one of the characteristic properties that define it. Other notable chemical substances include diamond (a form of the element carbon), table salt (NaCl; an ionic compound), and refined sugar (C₁₂H₂₂O₁₁; an organic compound).