Unit 1: Chemistry of Life - Water Properties Flashcards
Water Properties
What do all life on earth have in common?
They’re all made up of atoms
What 6 elements are abundant in living organisms?
Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur
Ionic bonding
A bond in which electrons are transferred from one element to another
What does ionic bonding result in?
Ions or charged particles
Cations
Positively charged
Anions
Negatively charged
Valence electrons
Electrons in the outermost shell
Covalent bonding
A bond that is formed when electrons electrons are shared between elements
What does electronegativity stand for?
High electronegative atom
Electronegativity
An atom which has a strong pull on another atom’s electrons
What does electronegativity result in?
Partial charges
Non-polar covalent bonds
Equal sharing of electrons
Examples of 2 non-polar covalent bonds
O2, CO2
Polar covalent bonds
Unequal sharing of electrons
What happens in polar covalent bonding?
An electronegative atom will pull on another atom’s electrons
What does polar covalent bonding result in?
Unequal charges
Example of polar covalent bond
H2O
How are electrons shifting in a water molecule?
Oxygen pulls on the two hydrogen atoms’ electrons
What are the partial charges in a water molecule?
H is partially positive, O is partially negative
How would you classify the bond between an H and O in a water molecule?
Polar covalent
A molecule that contains S, P, O, F, or N is…
Polar covalent
Why are molecules that contains S, P, O, or N polar?
They are highly electronegative
A molecule that contains long hydrocarbon chains is…
Non-polar covalent
Symmetrical molecules are…
Non-polar covalent
Asymmetrical molecules are…
Polar covalent
Polar molecules =
Hydrophilic
Non-polar molecules =
Hydrophobic
If there is a charge on a molecule, it is…
Polar covalent
Hydrogen bonds
A weak attraction between a hydrogen atom and a partially negative atoms
Hydrogen bonds can exist in between…
Water molecules
The partially positive H in one molecule of water is attracted to…
The partially negative O in another molecule of water
Hydrophilic
Mixes with water
Hydrophobic
Does not mix with water
Examples of hydrophilic molecules
Glucose, NaCl
Examples of hydrophobic molecules
O2, CO2
A molecule with a partial positive or negative charge is…
Polar covalent
Cohesion
Water’s ability to stick to itself due to hydrogen bonds
Adhesion
Water’s ability to stick to other polar and charged molecules
Transpiration
Evaporation of water through the leaves of plants or trees
In a tree, what does cohesion do?
Allows water molecules to move up the tree
In a tree, what does adhesion do?
Prevents the back flow of water
Heat capacity
The amount of energy it takes to change the temperature of water
Why is heat capacity important for aquatic life?
It is important so there are no large temperature fluctuations
Heat of vaporization
Thermoregulation
How does heat of vaporization and thermoreguation work?
The body gets hot, causes sweat, sweat absorbs heat, cools down body
What is surface tension caused by?
A lack of water molecules at the surface
What happens to intermolecular forces at the surface of water?
Higher intermolecular forces
What is surface tension?
Tendency of liquids to shrink into the minimum surface area possible
What bond is responsible for the surface tension of water?
Hydrogen bonding
How is hydrogen bonding responsible for the surface tension of water?
Hydrogen bonding create a cohesive force that allows water molecules to stick together
How does the density of ice compare to the density of water?
Ice is less dense than water
Why is ice floating significant?
If ice had a higher density and sank, living organisms would get crushed by the ice
