Science - 2018-19

CH.4 d - Acids & Bases

The student will investigate and understand that chemical quantities are based on molar relationships. Key concepts include: 

d) acid/base theory; strong electrolytes, weak electrolytes, and nonelectrolytes; dissociation and ionization; pH and pOH; and the titration process.

Bloom's Level:  Analyze; Understand

Adopted: 2010

BIG IDEAS

  • Acids and bases are chemical opposites and can neutralize each other. 
  • pH is a logarthmic scale that describes the concentration of H+ ions. 

  • I can determine if a swimming pool is safe to get in.

UNDERSTANDING THE STANDARD

  • Two important classes of compounds are acids and bases. Acids and bases are defined by several theories. According to the Arrhenius theory, acids are characterized by the sour taste, low pH, and the fact that they turn litmus paper red. According to the Arrhenius theory, bases are characterized by their bitter taste, slippery feel, high pH, and the fact that they turn litmus paper blue. According to the Bronsted-Lowry theory, acids are proton donors, whereas bases are proton acceptors. Acids and bases dissociate in varying degrees.
  • Strong electrolytes dissociate completely. Weak electrolytes dissociate partially. Non-electrolytes do not dissociate.
  • pH is a number scale ranging from 0 to 14 that represents the acidity of a solution. The pH number denotes hydrogen hydronium) ion concentration. The pOH number denotes hydroxide ion concentration. The higher the hydronium [H3O+] concentration, the lower the pH.
  • pH + pOH = 14
  • Strong acid-strong base titration is the process that measures [H+] and [OH-]. 
  • Indicators show color changes at certain pH levels.

ESSENTIALS

In order to meet this standard, it is expected that students will

d)  differentiate between the defining characteristics of the Arrhenius theory of acids and bases and the Bronsted-Lowry theory of acids and bases.

     identify common examples of acids and bases, including vinegar and ammonia.

     compare and contrast the differences between strong, weak, and non-electrolytes.

     relate the hydronium ion concentration to the pH scale.

     perform titrations in a laboratory setting using indicators.


KEY VOCABULARY

acid-base indicator, acidic solution, amphoteric, Arrhenius model, basic solution, Bronsted-Lowry model, buffer, buffer capacity, conjugate acid, conjugate acid-base pair, conjugate base, end point, equivalence point, neutralization reaction, pH, pOH, salt, salt hydrolysis, strong acid, strong base, titration, weak acid, weak base


Updated: Nov 19, 2017