Chapter 2 Flashcards
(61 cards)
What are the types of bonds?
- covalent
- polar covalent
- non polar covalent
- ionic bonds
- hydrogen bonding
what is a covalent bond
when 2 atoms share pairs of electrons to complete their valence shells and reach stability
ionic bond
when the electronegatively for an atom is so strong that it is about to steal the electron away form the other. The electronegative atom that steals is called an anion. The one that is stolen from, is usually a metal and is called a cation.
polar covalent bonds
when one atom is more electronegative than the other, allowing is to pull the electrons closer to itself to create a dipole. Usually involving O, N and S
non polar covalent bonds
when the electrons are equally shared between both atoms in the covalent bond.
Usually involving C and H
what makes a bond weak?
When the energy to break the bond is larger than the thermal energy of them molecules themselves
what makes a bond strong?
when the energy to break the bond is smaller than the thermal energy of molecules themselves
what is hydrogen bonding?
When H is covalently bonded to an electronegative atom like C, N OR O, it becomes partially positive. Because of this, it can bond to another C, O or N in a reaction called hydrogen bonding
What is the strength of a hydrogen bonds?
they are generally weak as the thermal energy matches the energy of the bond. However, due to an addictive effect, the more bonds, the more it grows.
how does water act like a solvent
because it has both polar and non poplar sides, it can make polar molecules dissociate by attracting and surrounding them.
what is the hydrophobic effect
It is a thermodynamically favourable interactions that forces hydrophobic, non polar molecules to aggregate so they have less surface area interacting with the polar water molecules.
What is a van der waal interactions?
is the slight attractive force between molecules with dipoles
What are the life supporting properties of water?
- all 3 atoms can participate in hydrogen bonds
- both covalent bonds are highly polarized
- the structure is highly asymmetric
in room temperature…
non covalent interactions are constantly broken and reformed
which bond need more energy than visible light to break
covalent bonds
non polar molecules are
hydrophobic and do not dissolve in water because the water doesn’t seem any dipole from them
polar molecules are
hydrophilic because the water molecules sense their polarity
What makes a strong acids?
easily loses its H proton
a strong acid will have a _____ conjugate base
weak
a weak acid will have a ______ conjugate base
strong
What are macromolecules?
highly organized molecules that form structures that carry out activity in the cell
what are the 4 major categories of macromolecules?
- Nucleic Acids (made form nucleotides)
- Proteins ( made form amnio acids)
- Carbohydrates (made from monosaccharides)
- Lipids ( made from fatty acids)
What macromolecule is not always considered one and why?
Lipids because they are not always made be a repeat of monomer or connected to other monomers
What are functional groups?
particular grape of atoms that when together give a molecule specific properties, chemical reactivity and solubility in certain solutions.
