Name : Nikman Adli b. Nor Hashim. ( M04D )

Title : Ionic and covalent compounds.

Objective : 1. To observe and become recognizable with some of the properties of ionic and covalent compound.

2. To determine the relative conductivities of aqueous solutions of some ionic, covalent and polar covalent compound.

3. To be able to differentiate by conductivity measurements between strong, weak and non-electrolytes.

Results:

Data collection :

I. The conductivity of distilled and tap water :

Types of water Volume( + 0.05ml)

Ammeter readings(+ 0.01A)

Distilled water 100.00 0.01Tap water 100.00 0.03

II. Ionic and covalent substances :

Substances Relative mass Ammeter readings (A)

Observations

Sodium bicarbonate 1 0.20 Bubbles are formed around the electrodes

Aluminium sulphate 1 0.07 Bubbles are formed around the electrodes

Sucrose 1 0.00 Nothing happenEthylene glycol 1 0.00 Nothing happen

Magnesium sulphate 1 0.07 Bubbles are formed around the electrodes

Ethanol 1 0.00 Nothing happen

III. Effect of concentration on conductivity :

Concentration of NaCl(mol dm-3)

Ammeter readings (A) Observations

0.01 0.03 Lots of bubbles had been seen on both electrodes

especially cathode. 0.001 0.01 Little bubbles can be seen

on the surface of both electrodes

0.0001 0.01 Little bubbles can be seen on the surface of both

electrodes0.00001 0.01 Too little bubbles can be

seen on the surface of both electrodes

IV. Relative conductivities of partially and totally ionized polar covalent compound :

Substances Ammeter readings (A)Hydrochloric acid 0.02

Acetic acid 0.01Nitric acid 0.01Citric acid 0.01

Phosphoric acid 0.05Ammonia solution 0.01

1:1 mixture of acetic acid and ammonia 0.01

Data processing :

I. The conductivity of distilled and tap water

1. It is concluded that tap water is more conductive than distilled water.2. Distilled water which is pure water without the existence of mineral salt, can be

partially ionized to produce H+ and OH- ions. Hence the solutions hold these two ionic compounds and covalent water molecules. This is one of the reasons why water is a weak conductor.

3. Tap water contains other substances such as chloride ions, which clarify why they have greater conductivity than the distilled water.

II. Ionic and covalent substances

1. Substances that show the reading more than 0.00 A is an electrolyte which contains ionic compound. The reading shows the strength of the electrolytes, the bigger the reading on the ammeter, the stronger the substance be active as an electrolyte.

2. If the reading is 0.00 A, the substance is a covalent compound and also a non-electrolyte.

3. This gives the idea that ionic compound allows the current flowing while covalent compounds does not, which means that ionic substances are electrolytes while covalent substances are non-electrolytes.

III. Effect of concentration on conductivity

1. The bubbles at the cathode are actually hydrogen gas.2. The bubbles at the anode are oxygen gas.3. At the cathode, two cations which are sodium and hydrogen ions are attracted.

But the hydrogen ions have more tendencies to be ionized first due to its position in the electrochemical series.

4. At the anode, two anions which are hydroxide ions and chloride ions are attracted. But the hydroxide ions have more tendencies to be ionized first due to its position in the electrochemical series.

5. If the concentration of the solution is decreased, the number of ions that allows the current flow will also decrease which result in lower conductivity.

IV. Relative conductivities of partially and totally ionized polar covalent compound

1. Hydrochloric acid and phosphoric acid are fully ionized when diluted into water. This explains why they have higher ammeter readings compared to the others.

2. Acetic, nitric and citric acids are weak acids. They are partially ionized when diluted with water which makes them weak conductors. Likewise, Ammonia is a base instead being an acid.

3. From the experiment we can know that phosphoric acid has the highest conductivity compared to the others because the acid produces more H+ ions when diluted.