Compounds may be classified in several ways:
A. Accordingly to Origin:
- Inorganic Compounds – these are compounds of all elements except Carbon.
- Organic Compounds – these are compounds of Carbon.
B. According to its Electrical Conductivity
- Electrolytes – these substances whose aqueous solutions are capable of conducting electricity. They are classified as strong and weak electrolytes and may be acids, bases or slats. They are ionized.
- Non-electrolytes – these substances whose aqueous solutions do not conduct electricity. They are molecular and therefore will not conduct electric current.
C. According to the kind of element present
- Acids – compounds containing H+ ions in solution which when ionized break up into H+ and anion.
- Bases – compounds containing OH–in solution which when ionized break up into a cation and OH–.
- Salts – compounds containing a cation except H+ and anion except OH–. Salts are formed from the reaction of a base with an acid (neutralization reaction). They are usually ionic or electrovalent compounds and are strong electrolytes.
D. According to Chemical Bonding
- Ionic or Electrovalent Compound – compounds resulting from the formation of ionic bond between the elements (transfer of electrons).
- Covalent Compounds – compounds resulting from the formation of covalent bond (sharing of electrons) between the elements present.
1. Organic and Inorganic Compounds
Heat a pinch of sugar and salt in separate clean and dry test tubes. Observe and classify each compound.
2. Electrolytes and Non-Electrolytes
Test the electrical conductivity of the solutions and solids listed below by immersing the electrodes of the conductivity apparatus in each solution or solid samples. In each case, note the conductivity from the degree of brightness of the bulb. Use the words very bright, dim or not light to describe the glow on the bulb of the apparatus.
Note: Before each new solution is tested make sure that the electrodes have been thoroughly rinsed with distilled water and wipe when the apparatus is switched off.
Solutions: NaCl, NaOH, H2SO4, NH4OH, CH3COOH, C12H22O11, HCL, CuSO4, (NH4)2CO, C2H5OH, C3H8O3
Solids: KNO3, NACl, sugar crystals
3. Procedures on Acids and Bases
A. Test the action of the following acids and bases on the indicators given:
Acids: CH3COOH, HCL
Bases: NH4OH, NaOH
Indicators: blue litmus paper = phenolphthalein; red limus paper = methyl orange
B. Test the action of the following substances on blue and red litmus paper. Classify them as to acidic or basic:
- Soap solution
- Calamansi juice
- Baking powder
- Soft drink
A. For few milliliters (ml) of NaOH solution, add a drop of phenolpthalein indicator. What color is being produced? To this solution, add few ml of diluted HCl until a very light pink color is obtained. Heat the solution to dryness in an evaporating dish. What is left in the disk? Define neutralization.
B. To 5 ml. of sodium sulfate solution, add 5 ml. of BaCl2 solution. What is formed?