Acids, bases, salts and ionization Flashcards
- A water molecule is able to self-ionize.
- In pure water, a very small amount of water molecules ionize into hydrogen (proton) and hydroxide.
- There are always equal parts of H+ and OH- in pure water.
- Therefore the pH of water is neutral (7).
Hydrogen and Hydroxide ions
The measurement of H+ in a solution.
- Equal amounts of H+ and OH- is a neutral solution and has a pH of 7.
- pH of less than 7 are acidic, more H+ than OH-
- Less H+ than OH- is a basic solution, pH is greater than 7
pH
The amount of H+ in a solution is calculated as a molar concentration.
- 1 mole = 6.023 X 10 to the 23rd.
Determining the pH
Compounds that release H+ in a solution.
- Adding this to water will lower the pH.
- Dissociates in water :
HA => A- + H+
Acids
Compounds that release OH- in a solution.
- Adding this to water will increase the pH.
- Dissociate in water
- React with water to produce OH-
- General formula:
XOH => X+ + OH-
Bases
- Appear as all three states of matter, but liquid is most common.
- Pure molecules are usually dry crystals and are extremely hygroscopic.
- Binary
- Ternary
General properties of acids
Pull water out of the air to them.
Hygroscopic
Contain H+ and one other non-metal (HCl, HF, HBr)
Binary acids
Contain H+, O, and one non-metal radical.
Ternary acids
- Also called alkaline compound
- Bitter taste (physical property)
- Bases can appear in all three states, but most commonly found as greasy, slippery, powder form.
- All ternary compounds because they all contain O and a metal.
General properties of bases
States that acids dissociate into an aqueous solution to yield H+ and bases dissociate into an aqueous solution to yeild OH-
- The most commonly used biochemical definition for an acid and base.
Arrhenius theory
Defines acids as proton donors and bases as proton acceptors.
- Conjugate acid-base pairs differ by a single proton
- Amphorteric compounds can act as either a base or an acid.
Bronstead- Lowery Theory
States that an acid is any substance that accepts a pair of electrons and a base is any substance that donates a pair of electrons.
Lewis theory
- Acids can be added to basic solutions to decrease the pH
- Bases an be added to acidic solutions to increase the pH
- A neutralization reaction results in a pH of 7.
Acid-base reactions
A reaction with the product being a salt and water.
Neutralization
Ionic compounds and are neutral in water.
Salts
- 2 Ionic compounds are mixed together (acid and base)
- Ionic compounds split apart into their respective anion and cations.
- The cations will swap anions.
- A reaction occurs if, by swapping anions, a product is formed that cannot split apart into anions and cations- or what is known as an insoluble precipitate (salt) or gas.
Double replacement/ Neutralization
Contains a metal and a non-metal molecule.
Inorganic salt
Joining one metal and one non-metal element.
Binary salt
All H+ in the acid have been replaced by a metal.
Normal salt
Only some of the H+ in the acid have been replaced by a metal.
Acid salt
Contain one or more replaceable -OH.
Basic salt
Oxides of metals and non-metals.
Anhydrides
Form acids when placed in water.
Acid anhydride
Form bases when placed in water.
Basic anhydride
Substances that prevent major changes in pH by absorbing excess H+ or OH-.
- Maintaining the optimum pH for the organism is part of maintaining homeostasis.
- Blood contains these and therefore resist major fluctuations in pH.
Buffers
Contain water in their formula. Compounds that have water held in them.
Hydrates
Water held within a hydrate.
Water of crystallization
Have the water of crystallization removed by dehydration.
Anhydrous
- Some hydrates can attract more water from the atmosphere.
- hydrophilic or hygroscopic
- Deliquescent
- Efflorescent
- Compounds in the prep room that are known to be hygroscopic or efflorescent need to be kept tightly sealed so water doesn’t get in or escape.
Descriptions of hydrates
If something can attract so much water from the air that they dissolve.
Deliquescent
Spontaneously release water.
Efflorescent
Draw moisture from tissue.
Hardening compounds
Plaster of paris and gypsum are two different hydrates of this compound.
Calcium sulfate (CaSO4)
For the embalmer, you are interested in counteracting this in the biological sense.
- It can also occur in inorganic substances such as salts (not all salts)
- The properties are the same.
Hydrolysis
Double replacement reaction involving salt and water.
- Similar to neutralization in that you have an acid and a base (which is neutralized into a salt and water).
- Dissimilar because you make an acid and base of different strength. (strong acid and weak base, or weak acid and strong base).
Hydrolysis
Allows you to determine the relative strength of an acid or base.
- red and blue
- The strong member of a hydrolysis solution would cause a change in the litmus paper while the weak would not.
Litmus reactions
