What is the exact denisty of water and whyy?

Question

good answers people... you all got different answersss...

Answer 1

There is no "exact" density because density for a fluid generally varies with pressure and temperature. The metric system was designed, or basically "rigged", so that liquid water at 4 C would have a density of 1.0 g/mL (also 1.0 g/cm^3). Liquid water is densest at this temperature. Liquid water is under most circumstances incompressible, which means that an increase in pressure will not increase its density (unlike water vapor, water in the gaseous state). However, under extremely high pressures, one must take a factor called the bulk modulus into account in order to calculate the exact density of liquid water at extremely high pressures (such as those at the bottom of the ocean).

Water has the unusual property of being less dense in its solid form than its liquid form (at moderate temperatures). This keeps inland bodies of water from totally freezing in the winter, which would kill off the aquatic life therein. Water is less dense as a solid because the crystal structure of ice has a certain geometry which leaves more space between particles. For this same reason, exerting pressure on ice causes it to melt. Since the particles are being pushed together, the crystal structure becomes unstable, and the water reverts to liquid state. For example, when a person is skating on ice, the weight of the whole person on those thin blades, creates a high pressure which melts the ice right below the skate. It is this thin layer of water on which the skater actually glides (not the ice). The ice in one spot usually re-freezes (since it is free to expand again) after the skater moves to a new spot, a process called regelation.

Answer 2

So.. the first answers weren't good enough? At 4 degrees Celsius water's density is 1 gram per cubic centimeter/milliter because the metric system was designed to have it work out that way. And I'm not being sarcastic, it really was.

Answer 3

The density of water is 1.0 gram per cubic centimeter (cc), by definition, not by calculation. In other words, water was defined as the standard against which the density of all substances would be measured. A gram is defined as the mass of one cc of water, and a ml is defined as equal to a cc. A density of 2.0 simply means twice the density of the standard - water.

Answer 4

Water as part of the earth was used in setting the metric measurements, so the density of pure water is exactly 1g/ml because the mass of 1 ml (or cubic centimeter) of water was how they determined what a gram was. The meter was a part of the circumference of the earth, although now it is the length of a specific wavelength of light.

Answer 5

The density varies with temperature and pressure, though
only slightly. Here is a reference that gives the density of water in
grams per milliliter at various temperatures and (I presume) 1
atmosphere pressure:

Density / Vapor Pressure of Water (North Carolina State University)
http://www.ncsu.edu/chemistry/resource/H2Odensity_vp.html

At 70 degrees F (close to 21 degrees C) the density is 0.9979955 g/mL.
We can convert this to lb/gal as follows:

0.9979955 g 1000 mL 3.785411784 L 1 lb
----------- * ------- * ------------- * ----------- = 8.328676 lb/gal
1 mL 1 L 1 gal 453.59237 g

Answer 6

Scientists often indicate the density of a substance by using another measurement called specific gravity. Specific gravity is the density of a substance divided by the density of another substance that is used as a standard. For solids and liquids, water at 4°C (39°F) is usually the standard. Gold has a density of 19.3 g/cm3, so its specific gravity is 19.3 g/cm3 divided by 1 g/cm3 (the density of water at 4°C), or 19.3.

Answer 7

Its almost 1g/cc at 4C but not quite.

This is because the cgs system was designed to have a reference mass in terms of a volume of water at 4C. However, the SI system was not - it was and still is based on a reference mass held at a lab in Sevres, France. The cgs system is now redefined in terms of the reference units of SI.

So the density of water at 4C is now 999.974 kg·m-3, or 0.999974 g/cc.

Answer 8

Plug these keywords into Yahoo or Google:

"density", "water"

Note that the density of any substance depends on temperature.

Answer 9

The density of water is 0.1

Answer 10

this is why they call it learning....means you LEARN...doesn't mean you get answers from everyone else.

to go about life this way will be a short and miserable life.