Water Flashcards
Why is water is said to be a dipolar molecule?
Water is made up of 2 hydrogen atoms and 1 oxygen atom but the oxygen atom has a slight negative charge while hydrogen has a slightly positive charge so it’s said to be dipolar.
What bond does it form between water and hydrogen?
Weak hydrogen bonding because different poles attract so the positive pole of one water molecule will be attracted towards the negative pole of another water molecule. Hydrogen bonds cause the water to be able to stick to each other.
Why does water acts as a buffer solution against sudden changes in temperature?
Because water molecules have unique properties and can stick together so it would take more energy to break them than it would when they are not bonded together. Without the hydrogen bond, water will just be gas, due to the hydrogen bonds, water tends to have a high specific heat capacity and can act as a buffer against sudden temperature variations.
What is latent heat of vaporisation of water?
The energy required to evaporate 1g of water and due to hydrogen bonds, it needs a lot of energy to evaporate it.
Why sweating helps mammals to cool down?
Because evaporation of water e.g. sweat needs body heat to evaporate the water, therefore, it releases the heat within the mammal.
What is cohesion?
The tendency of molecules sticking together.
Why does water have a large cohesion force?
Due to its hydrogen bonding, water molecules are strongly stuck together and it can be pulled up through tubes e.g. xylem vessel.
What is surface tension?
Due to cohesion, water has a high surface tension where water acts as a skin and allows small organisms e.g. pond skaters to walk on it.
What is the importance of water in metabolism?
- It is used during condensation and hydrolysis reactions.
- Chemical reactions take place in an aqueous medium.
- Water is a major raw material in photosynthesis.
Why is water important as a solvent?
- Water dissolves gases e.g. O2, CO2
- Wastes e.g. ammonia and urea
- Inorganic ions and small hydrophilic molecules e.g amino acids, monosaccharides, ATP
- Enzymes, when they react in solutions
What other important roles does water have?
- Through evaporation, water cools organisms and allow them to control their temperature.
- It’s not easily compressed so it provides support.
- It’s transparent so aquatic plants can photosynthesize.
Where are inorganic ions found?
Inorganic ions are found in organisms where it’s in solution in the cytoplasm of cells and in body fluids.
Their concentration varies from very high to very low.
