1 / 23

Acids and Bases

Acids and Bases. Ionization of Water. Only happens to a small amount of water molecules H 2 O separates into ______________ Not the whole story H+ never occurs on its own In reality, another H 2 O molecule picks it up and becomes ___________________. Acids and Bases.

ziva
Télécharger la présentation

Acids and Bases

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Acids and Bases

  2. Ionization of Water • Only happens to a small amount of water molecules • H2O separates into ______________ • Not the whole story • H+ never occurs on its own • In reality, another H2O molecule picks it up and becomes ___________________

  3. Acids and Bases

  4. Classifying Acids and Bases • Arrhenius • Acid- substance that dissociates into ______________ • For Example: ___________________ • Base- substance that dissociates into ______________ • For example: __________________ • Does not explain bases without an OH ion

  5. Classifying Acids and Bases (cont) • Brønsted-Lowry • Acid - _______________ • For example: HCl and H2SO4 • Base - ________________ • For example: NH3 and OH-

  6. Conjugate Acid and Bases • Occur on the other side of acid base equations. • Lets look again at • NH3 is a ________. It will accept a proton (H+) • H2O is an _______. It will donate a proton (H+) • NH4+ is NH3’s _____________. It can donate a proton (H+) to become NH3 again • OH- is water’s ______________. It can accept a proton (H+) to become H2O again

  7. Amphiprotic • Amphiprotic – • Substances that can act like an acid or a base • Water is an amphiprotic substance. • H2O can accept a proton to become H3O+ • H2O can donate a proton to become OH-

  8. Strength of Acids and Bases • Depends on how much they dissociate in water • Strong • Considered to dissociate _____________ in water • Weak • Only partially dissociate in water • Reaction is _____________________ • Conjugate pairs • Strength is ______________________ • For example: Strong acids have weak conjugate bases

  9. Acids • Strong acids • ________ • ________ • ________ • ________ • ________ • ________ • ________ • All have 100% of the molecules break apart. There is no reverse reaction. • Weak acids • All others

  10. Polyprotic Acids • Have multiple ______ • H2SO4 • H2SO4 gives up 1 H+ to form HSO4- • This happens to ______ of the molecules since H2SO4 is strong • HSO4- gives up another H+ to form SO4-2 • This only happens to some HSO4- because it is _______ • Solution will contain • _________ of water molecules • H3O+ molecules (mostly from the first H+ but some from the second and from ionization of water) • HSO4- • a little bit of SO4-2 • A little bit of OH- (from the ionization of water)

  11. Acid Names • Binary acids (______________) • Prefix __________ • Root of element name • Suffix ___________ • Add acid • For example: HCl is ___________________ • Acids with Oxygen (_________________) • Root name of polyatomic (with polyatomic prefix if applicable) • Some polyatomic roots are modified slightly to be easier to say • Suffix • -ic with polyatomics ending in _______ • -ous with polyatomics ending in _______ • Add acid • For example: H2SO4 is ______________

  12. Bases • Strong bases • Group 1 metals with OH- • Ca, Sr, and Ba with OH- • These three are not very soluble in water, but the amount that does dissolve ionizes completely. • Weak bases • All others

  13. Chemical Equilibrium • Reversible reactions • Indicated with a _________ • Both reactions are happening at the same time • System reaches equilibrium when both are happening at same _____ • At equilibrium • Could have lots of reactant and little product • Could have lots of product and little reactant • Could have equal amounts of both • Changes to the system can shift equilibrium • Temperature • Pressure • Adding reactants or products

  14. Equilibrium Expressions • Mathematical way to represent equilibrium • For the equation, ________________________ • K = [C]c [D]d [A]a [B]b • K is the equilibrium constant for the equation • [ ] indicates the concentration of each substance in mol/L (M) • _______________ are not entered into the expression

  15. Ionization of Water • 2H2O(l)  H3O+(aq) + OH-(aq) • This equilibrium ___________________ • In other words, there is far more water molecules than hydronium and hydroxide ions in a sample • Kw = ________________ • Kw = 1.0 x 10-14 • In pure water and neutral solutions, [H3O+] and [OH-] are 1.0 x 10-7 M • In acidic solutions, ____________________________ • In basic solutions _____________________________

  16. pH • pH • Stands for potential of Hydrogen (really hydronium) • ______________ scale • pH = -log [H+] or [H+] = 10-pH • Values between 0-14 with each number representing a 10-fold increase from the previous number • pH  7 is ________ • pH = 7 is ________ • pH  7 is ________

  17. pOH • pOH = -log [OH-] or [OH-] = 10-pOH • Opposite scale • pOH  7 is ________ • pOH = 7 is ________ • pOH  7 is _________

  18. Indicators • Compounds that change color in the presence of different levels of pH

  19. Soil pH 5.0-5.5 Soil pH 6.0-6.5

  20. Neutralization (Acid-Base Reaction) • Special type of double displacement reaction • Acid + Base  ___________________

  21. Titration • Process of neutralizing an acid (or base) with an unknown concentration with a base (or acid) of a known concentration • Moles of H3O+ must equal moles of OH- for neutralization to occur • Often indicators are used to determine the end of the reaction • VaMa = VbMb • Va = volume in L of acid • Ma = molarity of acid • Vb = volume in L of base • Mb = molarity of base

More Related