Solutions, pH and buffer systems Flashcards
What are the 3 types of intermolecular forces?
Hydrogen bonds
Dipole interaction
London Dispersion Forces
What are Intermolecular forces?
-The Attractive forces that act between 2 molecules
- Weaker than chemical bonds (intramolecular forces)
- Strength is generally less than one- tenth that of a single covalently bond.
- The greater the strength the higher the boiling point.
main things to know about Dipole-Dipole Interactions
-Occur between POLAR molecules
- The positive ends of one molecule attract the negative end of another molecule
-Strength depends on the extent of molecular polarity.
main things to know about hydrogen bonds
- Extra strong Dipole-dipole interactions
- Require the presence of hydrogen covalently bonded to a small, very electronegative atom (F,O or N)
- Interaction is between the H atom and a lone pair of electrons on another small electronegative atom (F, O or N)
main things to know about London forces
- Occur between ALL molecules
- the only type of intermolecular force present between NONPOLAR molecules.
- Instantaneous dipole-dipole interactions caused by momentary uneven electron distributions in molecules
- The weakest type of intermolecular force, but important because of their sheer numbers.
What is the Mole?
The amount of a substance that contains as many particles
(atoms, molecules or formula units)
1 mole = 6.02 x 1023 < small 23
What are the components of a solution? and what is it?
Solvent: Component of a solution that is
present in the greatest amount. remember venti is the biggest type of coffee
Solute: Component of a solution that is present
in a lesser amount relative to that of the
solvent. remember ute is half a car
A solution is a homogeneous mixture of two or more substances with each substance retaining its own chemical identity.
is a solute able to be separated from the solution?
Yes the solute can be separated from the solvent by physical means e.g., evaporation.
What is solubility?
Solubility The maximum amount of solute that will
dissolve in a given amount of solvent under a given set of
conditions
what is it called when something has low solubility?
insoluble
What is it called when something has high solubility?
Soluble
What is a saturated solution?
A solution that contains the maximum amount of solute that can be dissolved under the conditions at which the solution exists
What is concentration and what are the two methods of expressing concentration?
The amount of solute present in a specified
amount of solution
- Molarity concentration
- Percent concentration
what are the three different ways of representing percent concentration?
- Percent by mass (mass–mass percent)
- Percent by volume (volume–volume percent)
- Mass–volume percent
What is hypertonic, hypotonic and isotonic solutions?
Hypotonic: A solution with a lower osmotic pressure than that within
cells. The cell has too much of the solvent (e.g., water) therefore it will look swollen. the net flow of water into the cells.
Hypertonic: A solution with a higher osmotic pressure than that
within cells. A cell has too little of the solvent (e.g., water) therefore will look dried up. The net flow of water out of the cells.
Isolotonic: A solution with an osmotic pressure equal to that within
cells. equal water flow into and out of the cells. The cell will look perfect.
Characteristics of an acid
- Produce H+
- is an electrolyte
- Taste sour
- May sting
- Will neutralize bases.
- Will always start with a H and have acid in the name
Characteristics of a base
- produce OH-
- Is an electrolyte
- Tastes bitter chalky
- Soapy, slippery
- Will neutralize acids
- will always end with an OH and hydroxide
What is Arrhenius acid-base theory?
Arrhenius acid: Hydrogen-containing compound that produces H+ ions in solution
Arrhenius base: Hydroxide-containing compound that produces OH– ions in solution
What is Bronsted-Lowry acid-base theory?
Brønsted–Lowry acid: Substance that can donate a proton (H+ ion) to some other substance Proton donor.
Brønsted–Lowry base: Substance that can accept a proton (H+ ion) from some other substance Proton acceptor.
examples of an acid
nitric acid
hydrochloric acid
sulfuric acid
chloric acid
carbonic acid
Examples of bases
Lithium hydroxide
sodium hydroxide
potassium hydroxide
calcium hydroxide
aluminum hydroxide
What are weak acids used?
Food and household products
What are weak bases used?
cleaning products
Name the following
HCL
H2CO3
NaOH
H3PO4
KOH
HCL= hydrogen chloride
H2CO3 = Carbonic acid
NaOH = sodium hydroxide
H3PO4 = phosphoric acid
KOH = potassium hydroxide
What is the difference between a strong acid and a weak acid?
strong acids dissociate completely into ions in solution whereas a weak acids only a few molecules dissociate
What is the difference between strong bases and weak bases?
strong bases dissociate completely into ions in
solution whereas weak bases yield few hydroxide ions
What is the Neutralization Reaction?
The chemical reaction between an acid and a
hydroxide base in which salt and water are the
products
What are salts?
- Ionic compounds containing a metal or polyatomic ion as the positive ion and a nonmetal or polyatomic ion (except hydroxide) as the negative ion.
- All common soluble salts are completely dissociated into
ions in solution - Not classified as an acid or base
- Dissolve in water
- Ionically bond.
Key points of pH
- A compact way to represent solution acidity
- pH decreases as [H+] increases
- pH range between 0 and 14 in aqueous solutions at 24°C
What is blood pH?
7.35-7.45
where on the pH scale do bases sit
8-14
Where on the pH scale do acids sit?
0-6
What is a buffer?
Buffer: An aqueous solution containing a substance that prevents major changes in solution pH when small amounts of acid or base are added to it.
Typically, a buffer system is composed of a weak acid and its conjugate base.
Buffers Contain Two Active Chemical Species:
1. A substance to react with and remove added base
2. A substance to react with and remove added acid
What is an electrolyte?
A substance whose aqueous solution conducts electricity
Example - Strong acids, bases, and soluble salts
What is a nonelectrolyte?
They do not conduct electricity. Example - Table sugar
(sucrose) and glucose
What is a weak electrolyte?
They incompletely ionize/dissociate into ions.
Example - Weak acids and bases
What is air made out of
Oxygen (solute and Nitrogen (solvent)
