What are important properties of water?

Question

i have a bio test tomorrow and i have a study guide but i just need extra help

Answer 1

Chemical and physical properties of water:
Water has the chemical formula H2O meaning that one molecule of water is composed of two hydrogen atoms and one oxygen atom. It can be described ionically as HOH, with a hydrogen ion (H+) that is bonded to a hydroxide ion (OH-). It is in dynamic equilibrium between the liquid and vapor states at standard temperature and pressure. Water alone is a colorless, tasteless, and odorless liquid, but upon standing it takes on the traces of carbon dioxide in the air and trends toward a sour solution of carbonic acid that is unpleasant-tasting and more inhospitable to life.

Water is often referred to in the sciences as the universal solvent and the only pure substance found naturally in all three states of matter; however, "found" should not mean that water is the only such natural substance that can be in three states at regular Earthly conditions, as its two elements are much more abundant than those of at least ten other molecules that share water's range but that are often found dissolved in water or shale. Examples are acetic acid, formic acid, hydrazine, dioxane, and benzene.

Color:
Water strongly absorbs infrared radiation. As infrared radiation is next to red-colored light on the EM spectrum, a small amount of visible red light is absorbed as well. This results in pure water appearing slightly blue, when seen in mass quantities such as a lake or ocean. The blue color can easily be seen as one sees the blue color of the sea or a clear lake under an overcast sky, which means that it is not a reflection of the sky. In practice, the color of water can vary strongly, depending on impurities. Limestone turns bodies of water turquoise, while iron compounds turn it red/brown and copper compounds create an intense blue. Algae commonly colors water green.

Solvation:
Water is a very good solvent, dissolving many types of substances. The substances that will mix well and dissolve in water (e.g. salts) are known as "hydrophilic" (water-loving) substances, and those that do not mix well with water (e.g. fats and oils), are known as "hydrophobic" (water-fearing) substances. The ability of a substance to dissolve in water is determined by whether or not the substance can match or better the strong attractive forces that water molecules generate between themselves. If they cannot, the molecules are "pushed out" from amongst the water, and do not dissolve.

Cohesion and adhesion:
Water sticks to itself (cohesion) because it is polar, meaning one end of the molecule has slightly more negative charge than the other, which has slightly more positive charge. In water, this happens because the oxygen atom is more electronegative—that is, it has a stronger "pulling power" on the molecule's electrons, drawing them closer (along with their negative charge), and making the area around the oxygen atom more negative than the area around both the hydrogen atoms.

Water also has high adhesion properties because of its polar nature.

Surface tension:
Water has a high surface tension caused by the strong cohesion between water molecules. This can be seen when small quantities of water are put onto a nonsoluble surface such as polythene: the water stays together as drops. On extremely clean glass the water may form a thin film because the molecular forces between glass and water molecules (adhesive forces) are stronger than the cohesive forces.

In biological cells and organelles, water is in contact with membrane and protein surfaces that are hydrophilic; that is, surfaces that have a strong attraction to water. Irving Langmuir observed a strong repulsive force between hydrophilic surfaces. To dehydrate hydrophilic surfaces—to remove the strongly held layers of water of hydration—requires doing substantial work against these forces, called hydration forces. These forces are very large, but decrease rapidly over a nanometer or less. Their importance in biology has been extensively studied by V. Adrian Parsegian of the NIH.[2] They are particularly important when cells are dehydrated by exposure to dry atmospheres or to extracellular freezing.

Capillary action:
Capillary action refers to the process of water moving up a narrow tube against the force of gravity. It occurs because water adheres to the sides of the tube, and then more water is pulled on top of that water through cohesion, which sticks to the sides of the tube. The process is repeated as the water flows up the tube until there is enough water that gravity can counteract the adhesive force.

Heat capacity and heat of vaporization:
Water has the second highest specific heat capacity of any known chemical compound, after ammonia, as well as a high heat of vaporization (40.65 kJ/mol), both of which are a result of the extensive hydrogen bonding between its molecules. These two unusual properties allow water to moderate Earth's climate by buffering large swings in temperature.

Freezing point:
A simple but environmentally important and unique property of water is that its common solid form, ice, floats on its liquid form. This solid phase is not as dense as liquid water because of the geometry of the strong hydrogen bonds which are formed only at lower temperatures. For almost all other substances and for all other 11 uncommon phases, the solid form is denser than the liquid form. Fresh water at standard atmospheric pressure is most dense at 3.98 °C, and will sink by convection as it cools to that temperature, and if it becomes colder it will rise instead. This reversal will cause deep water to remain warmer than shallower freezing water, so that ice in a body of water will form first at the surface and progress downward, while the majority of the water underneath will hold a constant 4 °C. This effectively insulates a lake floor from the cold. Almost all other chemicals are denser as solids than they are as liquids, and freeze from the bottom up.

Electrical conductivity:
A common misconception about water is that it is a powerful conductor of electricity, with risks of electrocution explaining this popular belief. Any electrical properties observable in water are from the ions of mineral salts and carbon dioxide dissolved in it. Water does self-ionize where two water molecules become one hydroxide anion and one hydronium cation, but not enough to carry enough electric current to do any work or harm for most operations. Pure water can also be electrolyzed into oxygen and hydrogen gases but without any dissolved ions, this is a very slow process and thus very little current is conducted. The taste advertised in spring water or mineral water derives from the minerals present, while pure H2O is tasteless. As such, purity in spring and mineral water refers to purity from toxins, pollutants, and microbes.

Answer 2

Water molecules have cohesion with eachother this sticks them together when they are travelling up the xylem and also adhesion to the walls of the xylem vessels to minimise the downward effects of gravity. This is important because these properties facilitate the movement of water up to the top of very tall trees through the capilliary effect in the xylem vessels when water evaporates from the leaves and more water moves up to take its place. The xylem work like long thin straws in the stems of plants.

Answer 3

i dont know how in depth you want the answer to be, but i can give you some topics:

has strong hydrogen bonds
an extremely good solvent
polarity....able to "attract" many molecules
is the reason plants are able to produce oygen (called splitting water)
comes in a solid, liquid, and gas
the liquid is more dense than the solid, which allows ice to float on water, which is important during the winter for sea animals because the floating ice on the water creates insulation for the sea animals below it
high surface tension
"sticky" property (cohesion): makes water able to stick to itself and build up, example: large trees take water from the ground through their roots, and the water has to travel UP the tree...this is how that is possible
affects temperature: have you ever noticed that when it rains outside while its hot the temperature cools? and when its cold outside and it snows, the temperature warms up. this is caused by the way water takes in and uses heat energy
etc....
I hope this helps you!

Answer 4

The most important one is that its boiling point is high. This is achieved by the non-covalent interactions that take place between oxygen and hydrogen atoms, called hydrogen bonds. As these bonds take place, the energy stored in the molecular matrix grows, so you require more energy to make water boil, than what would be theoretically expected from a molecule alike. Think for example in ethanol.

Answer 5

Water is polar (a lot of frozen water is at the earth's poles). The polarity is from the oxygen stealing electrons from the hydrogen on a temporary basis. This causes cohesion, water sticking together (water beading up on glass). Shall I go on???

Answer 6

The most important property is that you can drink it and thus stay alive. The second most important property is that you can make beer with it. There is no third important property.

Answer 7

The only compound that expands when it freezes.