![]() ![]() Water undergoes a process called autoionization as a liquid. Pure water is a good insulator, but deionized water is never completely free of ions. Low compressibility allows water in deep oceans with high pressure to only decrease by 1.8% in volume. The compressibility of water is so low that is often assumed to be incompressible. CompressibilityĬompressibility is a result of pressure and temperature. The salt adds to the salinity and density of the remaining water which sinks by convection. Ice still floats on the ocean, but the ice is near salt-free with a similar density to ice on bodies of freshwater. Salt content lowers the freezing point of the ocean by almost 2 C. High specific heat keeps the temperature of the water relatively stable through the winter so that marine life can survive. This allows fish and marine life to survive under the ice. This is why bodies of water may have a layer of ice on the surface but contain liquid underneath. As a result, ice is less dense than water, which has a decrease in density by about 10%. Negative thermal expansion is the increase in density between 32 and 39.16 F. Instead of undergoing thermal expansion, the density rises with temperature to a peak of 3.98 C and then decreases. ![]() This process is known as evaporative cooling. It absorbs excess body heat as it evaporates. Water’s high heat of vaporization allows humans to use sweat to cool off. This allows bodies of water to have minimal fluctuations in temperature to regulate climate. Water has a high specific heat of 4184J/(kg x K) at 20 C and high heat of vaporization because of hydrogen bonding. Water is amphoteric, meaning it can act as either an acid or a base depending on the solution. For example, NaCl separates into Na+ cations and Cl- anions surrounded by water molecules. Acids, alcohols, and salts are rather soluble in water while fats and oils are hydrophobic.Īn ionic solute dissolved in water becomes separated. If they cannot, the substance forms a precipitate. Substances can dissolve in water if they can match or overcome the hydrogen bonding between water molecules. Hydrophilic substances are those that dissolve in water, while hydrophobic substances do not mix well with water. For example, more energy is required to break hydrogen bonds, so water has a higher melting and boiling point. Hydrogen bonding is weaker than the covalent bonds between the oxygen and hydrogens of the same molecule but causes many of water’s unique properties. This attraction is called hydrogen bonding. The partial positive charge of the hydrogen of one water molecule attracts the partial negative charge of the oxygen of another water molecule. ![]() This difference in charge causes polarity. The difference in electronegativity between the oxygen and hydrogens causes the oxygen to have a partial negative charge and the hydrogen to have a partial positive charge. It has a bent molecular geometry with the oxygen having two lone pairs of electrons. One oxygen atom and two hydrogen atoms make a water molecule. The five main properties of water are its high polarity, high specific heat, high heat of vaporization, low density as a solid, and attraction to other polar molecules. Water molecules form hydrogen bonds and are extremely polar. It is also the only common substance to exist as a solid, liquid, and gas naturally. Water (H20) is the “universal solvent” and the most abundant surface on Earth. Polar Molecule- A molecule with a partially negative charged end and a partially positive charged endĮlectronegativity- Tendency for an atom to attract shared electrons in a chemical bond Introduction to Properties of Water Heat of Vaporization- Amount of energy required to transform a quantity of a liquid into a gas Specific Heat Capacity- Amount of energy required to raise the temperature of 1 kg of a material by 1 C You will also learn about the structure of a water molecule. In this tutorial on the properties of water, you will learn about the physical and chemical properties of water. ![]()
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