Solutions, pH, Buffers Flashcards
What is a mole?
A counting unit for chemists for atoms and molecules (due to sheer volume)
The amount of a substance that contains as many particles as there are atoms in pure (12)C
What is Avogadro’s number?
One mole = 6.02 x 10(23) objects
What is deposition?
Gas to solid (i.e. snow)
What is sublimation?
Solid to gas (i.e. dry ice)
What is formula mass?
The sum of the atomic masses of all the atoms present in a chemical formula in atomic mass unit (AMU) in a compounds formula
What are intermolecular forces?
An attractive force that acts between a molecule and another molecule
Involves positive and negative interactions
Intermolecular (weak), Intramolecular (strong - true chemical bonds)
What is a dipole-dipole interaction?
Intermolecular force that occurs between polar molecule (positive and negative end)
Greater polarity of molecules, greater the strength of this interaction
*not a chemical bond, an attraction**
What are hydrogen bonds?
Stron dipole-dipole bond with hydrogen containing molecules
Hydrogen is covalently bonded to highly electronegative element of a small atomic size (Fluorine, Oxygen, Nitrogen)
Determines the solubility of something
If something is insoluble, does that mean the hydrogen bond can be broken?
No, if something is soluble is means is CAN break the hydrogen bond
What are London forces?
Occurs between all molecules, only type of intermolecular force present between non-polar molecules
Weakest type of force
What are characteristics of solutions?
A homogenous mixture of two or more substances where each substance retains it’s own chemical identity
Has variable composite
Solutes can be separated by physical means, remains uniformly distributed
What are components of a solution?
Solvent (greatest amount in solution)
Solute (lesser amount)
What is solubility
The max amount of solute that will dissolve in a given amount of solvent under a given set of conditions
Low solubility (doesn’t dissolve)
High solubility (can dissolve)
What is a saturated solution?
A solution that contains the max amount of solute that can be dissolves under the conditions at which the solution exists
What does concentration refer to?
The amount of solute present in a specified amount of solution.
How can you express concentration?
Molarity
Percent concentration (by mass, by volume or mass volume percent)
What is a semi-permeable membrane?
A wall that is selective in passing things - water/other molecules trying to go through
Attempts to make concentration equal
What is Osmosis?
Diffusion of water across a semi-permeable membrane
Osmotic pressure - force of water passing through
What is tonicity?
The relative solute concentrations of two environments separated by a semipermeable membrane
What is hypotonic, isotonic and hypertonic?
HypOtonic (Out of vessel, into cells “swell” - can burst), less osmotic pressure
Isotonic (stays where I put it) - function cell of normal size
HypErtonic (enter vessel, out of cells “shrink”),
What is the purpose of the acid-base?
To ensure homeostasis, intracellular and extra cellular fluids must contain balanced quantities of acids and bases
Depending on concentration of hydrogen ions vs hydroxide ions, it is either acid or base
More hydrogen dissolved = more acidic
More hydroxide dissolved = more basic
What is the Arrhenius acid-base theory?
Acid = hydrogen containing compound that produces hydrogen ions in water
Base = hydroxide containing compounds that produces hydroxide in water
What is the Brønsted-Lowry acid-base theory?
Acid = any substance that can donate a proton to another substance
Base = any substance that can accept a proton from another substance
Proton donation (from acid) cannot occur unless acceptor (base) is present
What are polyprotic acids?
Acids that can transfer two or more hydrogen ions during an acid-base reaction
