Properties of Water

Water is a Polar Molecule The shape of a water molecule makes it looks like mickey mouse The oxygen side of the molecule has a slightly negative charge The hydrogen side of the molecule has a slightly positive charge This results in water being considered a polar molecule

Water Molecule

Water molecules form hydrogen bonds The slightly positive hydrogen atoms in the water molecule are able to attract the slightly negative oxygen atom of another water molecule This type of attraction forms a hydrogen bond Hydrogen bonds between water molecules are the cause of many important properties of water that are essential to life

Hydrogen Bonds

High Specific Heat Capacity The hydrogen bonds cause water to have a high specific heat capacity. Specific heat capacity is how resistant a substances is to changes in temperature This high specific heat capacity is very important to regulating our body temperatures. Think about what would happen if water did not have such a high specific heat capacity.

High boiling point Water boils at 212 F or 100 C This is fairly high boiling point compared to other substances This is also due to the hydrogen bonds formed between water molecules About 70% of the Earth is covered in water. The human body is 60 to 70% water. Why might the high boiling point of water be important to life?

Density Typically, the solid form of a substance will sink when placed in the liquid form of a substance. This is because the solid form of a substance usually has a higher density than the liquid form. Water is a unique substance because it’s liquid form has a higher density than its solid form (ice). What would happen if ice did not float on liquid water?

Density This unique occurrence is caused by the hydrogen bonds formed between water molecules.

Many compounds dissolve in water Many different substances are able to dissolve in water, making it an important solvent. The polarity of water is a big reason for this. Water is able to dissolve ionic compounds and polar molecules. This plays a very important role in dissolving sugars, salts, and proteins in bodily fluids (ex. blood).

Cohesion and Surface Tension The hydrogen bonds between water molecules cause water molecules to stick to each other. This is called cohesion. This is why water often beads up on surfaces This also produces surface tension which acts like a skin on the surface of water.

Surface Tension

Adhesion The polar nature of water also allows water to stick to other substances This is called adhesion This is very important for water transport through plants

Adhesion