Properties and Classification of Ionic and Covalent Compounds, Lecture notes of Chemistry

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Part K: What are covalent Compounds?

Covalent compounds have widely varying properties.

The plastic casing of a ballpoint pen, the components of gasoline, the strongly scentedcomponents in a banana, and the carbon dioxide that we exhale with every breath are all

covalent compounds.

Here are some properties that covalent compounds do share:

1. Covalent compounds have _____________________________________________.

are very strong, the bonds that attract one molecule to another inAlthough the forces that hold atoms together in molecules

a covalent compound are relatively __________________.

Therefore, when you __________ or ___________________ acovalent compound there is less

of a barrier to overcome so they will melt___________________________________________.

Part L: Properties of Covalent Compounds

2. Covalent compounds are relatively _____________________.

softness of covalent compounds.The ___________________ of the forces between molecules also explains the relative

3. Covalent compounds are poor ____________________________.

Unlike ionic compounds, covalent compounds do not have free ____________________or ions. This covalent compounds poor conductors of both heat and electricity.

Properties of Ionic Compounds Properties of Covalent Compounds

Procedure

Part 1: Melting Point

1. Put on your safety glasses and keep them on until you have finished cleaning up your lab station.

2. 3. Label your aluminum trays A, B, C, D, E.Place a very SMALL sample of each substance A, B, C, D, E on the matching aluminum

4. tray.Plug in your hot plate and turn it on medium/high.

5. Place two of the aluminum trays on the hot plate. Observe the substances in each tray and make note of which substances melt.

6. 7. If the substance does not melt right away continue to observe for 4 minutes.Using the tongs, remove aluminum trays from the hot plate and continue the procedure

with your next two samples.

Part 2: Solubility

1. Place one tube. SMALL scoop of each substance A, B, C, D, E into a separate clean test

2. 3. Fill the test tube ⅓ full with water and gently agitate the test tube for 3 minutes.Record your observations. Repeat this procedure for each of the test tubes.

Data

Substance Colour Melting Point: Does it melt? Solubility: Does it

dissolve?

Ionic or Covalent

A - sodium chloride chemical formula:

________

B - sucrose (C 12 H 22 O 11 )

C - potassium chloride chemical formula:

________

D - acetaminophen (C 8 H 9 NO 2 )

E - unknown

Analysis

1. Look carefully at your results. Do you see any patterns? Summarize the results from your experimental data on the last page based on whether you were observing an ionic

or covalent compound. If you don’t see any patterns, state “no pattern”. If you do see general patterns, state them.

Ionic Covalent

Melting Point

Solubility

2. Based on your experimental data and your analysis above, do you think the unknown compound was ionic or covalent? Why?

3. Can you think of another property we could test to determine if an unknown substance is an ionic compound or a covalent compound? Have a look at your notes for both types of

compounds if you can’t think of anything.

Positive Ions

NAMES, FORMULAE AND CHARGES OFSOME POLYATOMIC IONS

Negative Ions

NAMES AND FORMULAE OFCOMMON ACIDS

Hydrochloric acid

Sulfuric acid

Nitric acid

Acetic acid

NH 4 +^ Ammonium CH 3COO –^ Acetate

CO 3 2–^ Carbonate

ClO3–^ Chlorate

ClO2–^ Chlorite

CrO42–^ Chromate

CN –^ Cyanide

Cr2O72–^ Dichromate

HCO3–^ Hydrogen carbonate, bicarbonate

HSO4–^ Hydrogen sulfate, bisulfate

HS–^ Hydrogen sulfide, bisulfide

HSO3–^ Hydrogen sulfite, bisulfite

OH–^ Hydroxide

ClO–^ Hypochlorite

NO3–^ Nitrate

NO2–^ Nitrite

ClO4–^ Perchlorate

MnO4–^ Permanganate

PO43–^ Phosphate

PO33–^ Phosphite

SO42–^ Sulfate

SO32–^ Sulfite

PREFIXES

mono

ditri

tetrapenta

hexahepta

octanona

deca

HCl

H 2 SO 4

HNO 3

HCH 3 COO