Amy Saavedra document

THE PH SCALE
Learning Objectives:

To distinguish between acidic, neutral and alkaline solutions using pH values.
To classify solutions of equal concentrations in terms of acid or base strength using pH values.
To understand how the appropriate use of Litmus paper, Universal Indicator and pH meter can give an account of different degrees of accuracy in the measurement of acidity or alkalinity of substances.

1) Define what an Acid is. Give five characteristics of acids.
An acid is a chemical which, when dissolved in water yields a solution with an activity greater than hydronium cation pure water, that is, a pH below 7.
Characteristics of acids:
-Acids taste sour.
-Acids react strongly with metals, generally with the evolution of hydrogen gas
-Strong Acids are dangerous and can burn your skin.
-Acids change litmus red.
-Acids become less acidic when mixed with bases.
2) Write down the chemical formulae of five Acids.
-Sulfuric acid: H2SO4
-Boric Acid: H3BO3
-Carbonic Acid: CH2O3
-Citric Acid: H3C6H5O7
-Hydrochloric acid: HCl
3) Write down the chemical equation that shows what happen to acids when they dissolve in water.

4) What determines that some acids are stronger than others.
5) Describe how using Universal Indicators solution, blue litmus paper and pH meter can determine the acidity of a giving acid.
6) State at least 3 applications of uses of acids in medicine, human nutrition, food industry, and electrochemistry.
7) Describe with assistance of chemical equation, how acids react with:
a) MgOH
b) NaOH
c) CuO
d) NaHCO3
e) NH3
f) CaCO3