Differences Between Ionic And Covalent Compounds

Differences Between Ionic and Covalent Compounds

Abstract

In chemistry, a compound is a substance formed from two or more elements, with a fixed ratio determining the composition. A defining characteristic of a compound is that it has a chemical formula. Formulas describe the ratio of numbers of atoms in a substance. Compounds may have a number of possible phases. For a compound to be a liquid or a gas and still be called a compound, atoms from the various elements must be stuck together in the form of molecules. The formation of molecules is why compounds such as C2H4 exist. The formula is telling you not just the ratios but also how many atoms there are in each molecule (Wikipedia).

Ionic compounds are basically defined as being compounds where two or more ions are held next to each other by electrical attraction. One of the ions has a positive charge called a cation and the other has a negative charge called an anion. Cations are usually metal atoms and anions are either nonmetals or polyatomic ions. Usually, when we have ionic compounds, they form large crystals that you can see with the naked eye (4). A covalent compound is a compound in which the atoms that are bonded share electrons rather than transfer electrons from one to the other. While ionic compounds are usually formed when metals bond to nonmetals, covalent compounds are formed when two nonmetals bond to each other (3).

The solubility of a solute is the maximum quantity of solute that can dissolve in a certain quantity of solvent or quantity of solution at a specified temperature. (Jones)

Electrical conductivity is a measure of how well a material accommodates the transport of electric charge.(4)

Introduction

This experiement deals with solubility and electrical conductivity of ionic or covalent compounds. The purpose of this lab is to identify compounds as either ionic or covalent from the name and the formula, to observe and record the solubility and electrical conductivity or several ionic and covalent compounds, and to recognise the patterns among

some of the properties that will help to distinguish ionic compounds from covalent compounds.

Materials

6 Sheets of paper

6 test tubes

test tube rack

hot plate

250mL beaker

graduated cylinder

Benzoic acid (C6H5COOH)

Magnesium chloride (MgCl)

Paradichlorobenzene (C6H4Cl2)

Potassium iodine (KI)

Sodium nitrate (NaNO3)

Sucrose C12H22O11)

Ethanol

Procedure

1. Obtain six pieces of paper and label each piece with the name of one of the solids that you will test. (ethanol is a liquid). Estimate 2 grams of each substance and place on the appropriate piece of paper and divide the two grams into two equal piles.

2. Obtain six test tubes and a test tube rack. Label the test tubes 1-6 to correspond to the number in tables 1 and 2.

3. Begin heating approximately 150mL of water in a 250mL beaker on a hot plate. This will be used to determine the solubility of each substance in hot water.

4. Place 5mL of water at room temperature in each of the test tubes. Then put 1 g of each of the solids into the appropriate test tube, shake the test tube to dissolve the solids as much as possible. Shake from one to two minutes. If the substance dissolves it is soluble and if it does not it is insoluble. Record the results in your copy of table 1 in your note book.

5. Put any test tubes containing substances that did not dissolve in room temperature water into the beaker of hot water for two or three minutes. Again shake the contents. Record the solubility's in Table 1.