Kaylee
Properties of water
STRUCTURE OF WATER
HOW TO LABLE IT?
Add electrons to the shells. Label the two elements and type of the bonding found within a water molecule.
Covalent bonds share electrons.
POLARITY
The shared electrons are pulled towards the center of the central atom, making it partially negatively charged. The hydrogen atoms are partially postively charged. This makes molecules stick together though hydrogen bonding. The difference in charge across a molecule is called "polarity".
TRANSPORT OF WATER
The movement of water up through the xylem vessel of plants uses cohesion and adhesion
DENSITY
When water freezes, its molecules form a crystal line with more space between water molecules. This means ice is less dense than liquid water. This is why it floats on top. This is important for aquatic life as it stops ponds, lakes and oceans from freezing solid- Organisms below the ice layer can live as normal.
Sea ice is important for life as it provided a unique habit for some species e.g. polar bears.
SOLVENCY
Water is an universal solvent - it can dissolves many polar and iconic substances. For example, when an iconic compound e.g. salt, is added to water, water molecules surrounded each ion, dissolving it. Water dissolves many nutrients and minerals as it travels through the water cycle, which is important for the health of living things. It also acts as an important solvent in the cyto plasm of cells for metobolic reactions.
​
SPECIFIC HEAT CAPACITY
Water has a high specific heat capacity, which means it takes a lot of heat energy to raise its temperature. This means water can act as a buffer for changes in temperature. E.g. at the temperature of pond water does not change much throughout the day, even though the air temperature can change significantly. This creates a stable environment for the organism living there. Living things are mostly made up of water - water's high specific heat capacity helps us to maintain a stable body temperature.
LA TENT HEAT OF VAPORIZATION
To vaporize water, which means turning liquid water into a gas, the hydrogen bonds between water molecules must be broke. This requires a lot of heat energy, which is great for life on earth, as it means water is found as a liquid. Water's high heat is used to evaprate the sweat from our skin, which cools us down. As it takes a lot of heat energy, it means we can sweat without losing too much water.
TRANSPORT OF WATER
The movement of water up through the xylem vessel of plants uses cohesion and adhesion.
ADHESION
Adhesion is the attraction between differnt types of molecules. Water is attracted to other charged molecules. For example, glass is even more polar than water, so water is more attracted to it than to other water molecules. This allows water to "climb up" thin glass tubes-this is know as capillary action.
COHESION
Cohesion is the attraction between the same type of molecules. Water has strong cohesion due to it's polarity and the resulting hydrogen bonds between it's molecules . Cohesion gives water high surface tenison, which means it can resist external forces, e.g. pond skaters and water on a penny.
