VIETNAM SCIENCE ACADEMY

There are 6 main properties of water:

• Cohesion and Adhesion:

  • Cohesion is the attraction between two similar molecules 

  • For example: water molecule and water molecule .

  • Adhesion is the attraction between two different molecules

  • For example: water molecules and the leaf.

• High specific heat (nhiệt dung riêng):

  • Definition of specific heat:

  • The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.

  • The specific heat of water is 4.186 joule/gram °C which is higher than any other common substance.

  • This means that it takes more energy to raise the temperature of water by one degree Celsius than for example MgO (0.208 joule/gram °C).

  • The specific heat of water is high is because of hydrogen bonding which is the strongest intermolecular forces.

  • This is important because it helps to moderate temperature.

    • For example: Humans are 65% of water which helps us to stabilise our body temperature.

• High heat of vaporization (nhiệt bay hơi):

  • Definition of heat (enthalpy) of vaporization:

  • The quantity of heat that must be absorbed if a certain quantity of liquid is vaporized at a constant temperature.

  • For water to boil to 100 degree Celsius, it requires 2260 J/g.

  • This is important because it helps to moderate temperature.

    • For example: helping plants to cool, humans sweat.

• Universal solvent:

  • Because water is polar, it can dissolve nearly all ionic salts and polar molecules.

• Surface tension:

  • It is a measure of tension that is needed to break or stretch the surface of a liquid.

  • This is important because a habitat can survive on the surface of water.

• Low density of Ice:

  • When water becomes solid (ice), it becomes less dense and so it floats! 

  • This is important for fishes because this prevents lakes or oceans getting cold.

  • Water gets more dense until 4 degree Celcius but after that it gets less dense again.