What makes water unusual

This density trait is the engine for convection, one of the most important elements of the climate system; cold, salty water is heavy and sinks to great depths. It is replaced by water flowing in at the sea surface. This is called a dipole. It thus behaves differently from other substances in many ways. Ice is less dense and floats on the surface.

Freshwater has its greatest density at four degrees, and sinks to the bottom. This is then overlain by warm water. Salty water has different characteristics. Back to the page of origin Water — a unique molecule. Read our full whitepaper and discover how you can make sure that your pure water supply delivers the performance you need to produce reliable and accurate results.

Let's talk about lab water. Categories Analytical Chemistry. Science of the Future. Type your search. Water In The Lab. Why Is Water So Remarkable?

Water molecules are continuously moving and hydrogen bonds are breaking and reforming but hydrogen bonding is strong enough to be responsible for most of the unusual properties as described below: The increased attraction between water molecules raises its boiling point, making it a liquid at room temperature unlike its close neighbours in the periodic table which are all gases H2S, NH3, HF.

It's All About The Hydrogen Bonds Hydrogen bonding also results in a very high specific heat capacity and heats of vaporisation and fusion. Water Is An Effective Solvent The high polarity of water molecules makes it a highly effective solvent for ionic or polar species. Water is one of the few substances whose solid state can float on its liquid state!

When freezing, molecules within water begin to move around more slowly, making it easier for them to form hydrogen bonds and eventually arrange themselves into an open crystalline, hexagonal structure. So molecules are more tightly packed in water's liquid state than its solid state. This is why a can of soda can explode in the freezer. It is very rare to find a compound that lacks carbon to be a liquid at standard temperatures and pressures. So it is unusual for water to be a liquid at room temperature!

Water is liquid at room temperature so it's able to move around quicker than it is as solid, enabling the molecules to form fewer hydrogen bonds resulting in the molecules being packed more closely together. Each water molecule links to four others creating a tetrahedral arrangement, however they are able to move freely and slide past each other, while ice forms a solid, larger hexagonal structure. As water boils, its hydrogen bonds are broken.

Steam particles move very far apart and fast, so barely any hydrogen bonds have the time to form. So, less and less hydrogen bonds are present as the particles reach the critical point above steam. The lack of hydrogen bonds explains why steam causes much worse burns that water. Steam contains all the energy used to break the hydrogen bonds in water, so when steam hits your face you first absorb the energy the steam has taken up from breaking the hydrogen bonds it its liquid state.

Then, in an exothermic reaction, steam is converted into liquid water and heat is released. This heat adds to the heat of boiling water as the steam condenses on your skin. Common salt, which is made up of crystals of sodium chloride, easily dissolves in water because the hydrogen bonds pull the sodium and chlorine atoms away from the crystal, leaving them to float freely through the liquid.

Water is such a good solvent, in fact, that it is almost impossible to find naturally in a pure state; even producing pure samples in the laboratory is difficult. Almost every known chemical compound will dissolve in water to a small but detectable extent. Because of that, water is one of the most reactive and corrosive chemicals we know. That ability to interact with so many things is crucial for life. It means that water can dissolve a wide variety of nutrients and other ingredients and move them around our bodies.

Evolution has shaped these long, sophisticated molecules so that they have certain sections that easily mix with water, using hydrogen bonds, and other sections that shun water, like oil refusing to mix. The billions of protein molecules inside your body only fold into the right shapes to do their jobs because their interaction with water nudges them into the correct three-dimensional formats. Think of a liquid and it will most likely be water. Water is so common and so familiar that it is mundane: every day we drink it, touch it, wash with it, wet things, dry things, we boil it, freeze it and swim in it.

We live in a world where the environmental conditions allow us to explore the landscape of water at different temperatures and pressures; where it can slide comfortably between solid, liquid and gas or sometimes all three at once. The more we examine water, the stranger it gets.