Unit 4: Acids and Bases Flashcards
What are some properties of acids?
pH<7
Taste sour
Dissolve metals and form hydrogen gas
Conduct electricity (electrolytes)
What are some properties of bases?
pH>7
Taste bitter
Feel slippery
Conduct electricity (electrolytes)
What does water have to do with acids and bases?
They are only acids and bases when dissolved in water. For example, HCl(solid) is just hydrogen chloride (an ionic compound with no acid properties)
What are some uses of acids?
Some batteries.
Stomach acid.
Fertilizers.
Petroleum production.
What are some uses of bases?
Cleaning products
Soap
Medicine (like antacids)
Water treatment
Cement, mortar, and plaster.
How do you write the dissociation of acids and bases?
On the left, write the acid/base. On the right, write it broken apart into its ions. Remember that dissociation is reversible so double arrows must be used. Remember to write the physical states and charges.
What are the two theories of acids and bases?
The Arrhenius theory of acids and bases.
The Bronstead/Lowry theory of acids and bases.
What is the Arrhenius theory of acids and bases?
Svante Arrhenius discovered that the properties of acids and bases were caused by H+ ions and OH- ions when dissolved in water.
Both acids and bases dissolve in water to form ions. Water is usually not included, although there is evidence to show that H3O+ (hydronium) is produced.
What is the Bronstead/Lowry theory of acids and bases?
The noticed that some bases have not OH- ions.
Acids are compounds that donate a proton.
Bases are compounds that accept a proton.
What are conjugate acids/bases
In the reverse direction by the Bronstead/Lowry theory, acids become bases and bases become acids (conjugates).
What is an amphoteric substance?
A substance that can act as an acid in one reaction and a base in another. Such as HSO4.
What is a polyprotic acid?
An acid that can donate more than one hydrogen ion. The first H+ ion is the easiest to remove. Subsequent H+ ions are more difficult to remove because the compound gains a negative charge.
For example: H3C6H5O7 can lose 3 hydrogen ions. This means it has three dissolving reactions.
What is a strong acid?
An acid that dissolves completely in H2O and produces a high concentration of H+ ions. Strong bases are the same but with OH- ions instead of H+ ions. They are strong electrolytes.
What are weak acids?
They dissolve poorly in H2O and produce a low concentration of H+ ions. Weak bases are the same but with OH- ions instead of H+ ions. They are weak electrolytes.
What are ionization constants?
Because acid/base solutions are systems at equilibrium, we can write an equilibrium expression and solve for the equilibrium constant.
Ka: acid equilibrium constant
Kb: base equilibrium constant
Kw: Water equilibrium constant
Write the equations as normal equilibrium constant equations.
How do you use an ionization constant to determine which side is favoured?
Ka>1: products favoured (strong acid)
Ka<1: reactants favoured (weak acid)
Same for Kb.
Does water ionize?
Yes, but not well. It produces H+ and OH- ions. In pure neutral water, [H+]=1.0x10^-7 and [OH-]=1.0x10^-7.