Topic 2.2 - Water Flashcards
What is the chemical formula for water ?
H2O
What are the main properties of water ?
Cohesive, adhesive, solvent and thermal properties.
What is its other name regarding its solvent properties ?
Universal solvent
What are the two sides of polarity ? Give explaination
There is the hydrophilic aspect which allows water molecules to bind with other water molecules. There is also the hydrophobic aspect which allows water molecules to bind with each other.
What does cohesion mean ?
It means that water molecules tend to stick together thanks to the hydrogen bonds in between them.
What does adhesion mean ?
It means that water adheres to surfaces that are polar and therefore hydrophyllic.
Why do fats not dissolve in water ?
Fat molecules are non polar and are carried as balls of phospholipids.
Water is used or produced in two reactions, state their name and their effect.
Water is used in hydrolysis which splits a hydrogen molecule in two (catabolism). It is also used in condensation reaction to form or release a water molecule (anabolism).
How does a condensation reaction occur ?
Two molecules are joined together to form a larger molecule and a molecule of water. It is an anabolic reaction.
Give an example of when a condensation reaction occurs.
Condensation of two amino acids for a dipeptide and a water molecule.
Two monosaccharides linked form a disaccharide and a water molecule.
How does a hydrolysis reaction occur ?
Hydrolysis is the reverse of a condensation reaction. In hydrolysis, a large molecule is split into smaller molecules and water molecules are split into H and OH groups. It is a catabolic reaction.
Give an example of when a hydrolysis reaction occurs.
Polypeptides and water are broken down to create dipeptides or amino acides.
Polysaccharides and water are broken down into disaccharides or monosaccharides.
Glycerides and water are broken down to form fatty acids and glycerol.
