Chapter 1 : pH and Buffers Flashcards
Types of Chemical Bonds
- Ionic
- Covalent & Polar covalent
- Hydrogen
- Van der Waals
What type of bond is water ?
Polar Covalent .
The oxygens have a slight (-) charge while the hydrogens have a a slight (+) charge creating a difference in charge.
What is the universal law for solvents
” Like dissolves like”
polar molecules dissolve in polar solvents vice versa
Ionic compounds can create crystal structures called
Salts
Why do salts dissolve easily in water?
The positive part of water molecules attracts the negative chloride ions and the negative part of water molecules attracts the positive sodium ions.
Water has the highest interaction with what type of molecule ?
Polar molecules
Why do water molecules create “ cages” around non-polar molecules ?
Non- polar molecules
(CH bonds ) usually have no charge. Thus hydrogen bonds with itself to surround the molecule
In a low entropy state , water molecules are
highly ordered and structured
In high entropy states,water molecules are
less ordered and structured. Most are freely moving
What is an amphiphilic molecule ?
Molecules that are both polar and non-polar
Ex: fatty acids, phospholipids, micelles
How are fatty acids amphiphilic ?
The tails are nonpolar with CH bonds and the heads are polar with the hydrogen bonds
Why is the polarity of phospholipids so important
It helps to form the extracellular matrix or cell transport
H+ can also be represented as
H3O (+)
In acidic conditions , hydronium ions combine to form
H(+) + H20 -> H30(+)
In basic conditions, hydronium ions combine to form
H20 -> H(+) + OH (-)
What is the concentration of H+ at equilibrium ?
H+ = 1 x 10 ^(-7) M OH = 1 x 10 ^(-7) M
What is the concentration of H+ at acidic conditions?
H+ is greater than 1 x 10 ^(-7) M
OH is less than 1 x 10 ^(-7) M
What is the concentration of H + at basic conditions ?
OH is greater than 1 x 10 ^(-7) M
H(+) is less than 1 x 10 ^(-7) M
The Keq constant always adds up to
1 x 10 ^(-14) M
What is the Keq constant equation for water ?
Keq = [ H+] [OH-] ÷ [H20]
What is Kw
Kw = ionization of water constant which is 1 x 10 ^(-14) M
What is pH
ratio of H+ concentration vs OH- concentration. It is also based on the logarithmic scale.
What is the logarithmic equation for pH ?
pH = (-)log10[H+]
What are electrolytes ?
substances that when dissolved in water, conducts an electric current
