Chemical Bonding Lab PDF

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Types of Bonding Lab Nikhil Sharma | Ms. Warner | SCH3U9

Purpose: The purpose of this lab was to explore common chemical compounds and to differentiate between them by means of grouping them based upon their chemical properties. The collection of this data would show trends in melting points and electrical conductivity which would aid in the derivation of a means of categorizing these compounds into specific groups.

Hypothesis: Due to the properties of the compounds examined, it is most likely that they will be grouped as per their composition (i.e. Ionic, Covalent, Metalloid). It is predicted that the paraffin wax would melt first as covalent compounds are known to have lower melting points than that of ionic compounds. Additionally, metals would have the highest electrical conductivity but also the lowest solubility and Covalent compounds are not expected to conduct electricity in aqueous state.

Analysis: 1) Compare the chemical formulas for each of the compounds, including the ones looked up online, to their melting points. What patterns do you notice between these two? The data found shows a clear trend in an element’s respective melting and boiling points when contrasted with its chemical composition. Covalent Compounds (non-metals) were found to have significantly lower melting and boiling points, many of which are gaseous at room temperature. Ionic compounds however (metals) were found to have much higher melting and boiling points. The covalent compounds were mainly comprised of Hydrogen, Oxygen and Carbon atoms whereas the ionic were their own corresponding metals or a polyatomic with an attached metal.

2) Compare the formulas for each of the six compounds we evaluated in the lab to their abilities to conduct electricity in solution. What patterns do you notice between these two? The compounds given showed that metallic compounds (Copper, Zinc) were strong electrical conductors whilst in air however, due to the fact that they are insoluble in water, their electrical conductivity when aqueous could not be tested. However, covalent compounds proved to not conduct electricity at all while in their solid form and proved to be quite weak electrical conductors when dissolved in water. Since covalent compounds are formed by the sharing of electrons, there is no valence electron to be transferred, stopping the potential for electricity to flow.

3) Compare the formulas for each of the six compounds we evaluated in the lab to their appearance and shape. What patterns do you notice between these two? The compounds tested in the lab seem to have very similar patterns corresponding with their given categories. Compounds such as Sodium chloride, Epsom salt and sodium thiosulphate had uniform particles which were white in colour. They shared characteristics of metals from the first family of the periodic table. Metals such as copper and zinc were also very similar in their qualities. Copper, a hardshiny metal resembled the characteristics of zinc as it was shiny and hard. Aspirin and paraffin wax were quite similar in their characteristics as well since they were both quite soft and non-uniform and resembled properties similar to non-metals (covalently bonded).

4) Group each of the six chemicals and the chemicals researched online based on the type of bonding found in each chemical. For each group, list the properties that unite the group.

Bonding Type

Ionic Bond

Polar Covalent

Covalent

Compound

Formula

Sodium Chloride

NaCl

Sodium Thiosulfate

Na2S2O3

Magnesium Oxide

MgO

Epsom salts

MgSO4

Calcium Bromide

CaBr2

Calcium Hydroxide

Ca(OH)2

Copper

Cu

Zinc

Zn

Tungsten

W

Iron

Fe

Cobalt

Co

Aspirin

C9H8O4

Octane

C8H18

Carbon Tetrachloride

CCl4

Paraffin wax

C31H64

Acetylene

C2H2

The ionic bonds are united by recurring properties; they form crystals, have high melting and boiling points, are brittle, hard, and are good conductors. Some ionically bonded molecules such as sodium chloride and Epsom salt are good conductors when dissolved in water. Covalent bonds are united by their relatively low melting points and boiling points, they can burn easier than ionic compounds, they do not conduct electricity, are soft, and are mainly soluble in water. The only compound that was found as polar covalent was aspirin and it dissolved well in water as well as melted towards the end of the lab.

5) Tap water has a conductivity that is higher than deionized water. Research deionized water and suggest a minimum of three impurities or additives to tap water that might account for this observation. Be sure to cite your sources. The impurities you suggest must

be able to increase the conductivity of the water. Explain why they would increase the conductivity of the tap water. Tap water is water used for drinking, washing, and other daily chores. Conductivity is referred to as the ability to transmit heat, sound or electricity. Common elements such as Potassium, Chlorine, Magnesium, Iron and Sodium can be found in tap water. Many of these “impurities”, as previously mentioned, are good conductors of electricity as they are not only ions but that of metals. Metals are excellent conductors because the atoms in a metal form a matrix through which their outer electrons can move freely. Instead of orbiting their respective metal atoms, they form a "sea" of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions. Additionally, metals are known for being good conductors of electricity as found by the results of this lab and are the reason as to why tap water is a better conductor of electricity than deionized water.

Conclusion: To conclude, after performing the lab it was found that the ionic bonds have high melting points, are soluble in water, do not conduct electricity in their solid forms and were found to conduct electricity when dissolved in water. Covalent bonds were found to have low melting points and were soluble in water. They do not conduct electricity in their solid forms nor when dissolved in water. Aspirin was an exception due to the fact that the only electricity conducted was because of the polar bonds in water as well as the fact that dissolved aspirin creates Acetylsalicylic acid, a moderately conductive substance. The transitional metal (metallic bonds) seem to have high melting points and were strong conductors of electricity. Unfortunately, these metals are insoluble and their aqueous electrical conductivity could not be tested.

Observations: Hypothesis: Compound

Metal

Sodium Chloride Copper

Bonding

Melt On Hot Plate

Solubility in water

Yes

No

Yes

Yes

No

No

Zinc

Yes

Epsom Salt

Yes

Sodium Thiosulfate

Yes

Aspirin

No

Ionic

No

No

No

Yes

No

Yes

No

Yes

Yes

Yes

Covalent Paraffin Wax

No

Part A - Appearance: Compound

Description

Sodium Chloride

Appears to be a series of uniform, crystalline white particles

Copper

A hard, shiny brittle and twisted metal. Red-brown colour

Aspirin

Resembled soft, non-uniform white powder that formed chunks.

Zinc

A hard, silver, malleable metal in the shape of circles.

Paraffin Wax

A white, greasy, soft resin that is easily broken.

Epsom Salt

Uniform white particles that are similar to crystals.

Sodium Thiosulfate

A clear, large crystal-like structure that is white in colour.

Part B: - Melting Points It was found that the Paraffin wax melted first at approximately 4 minutes, followed by the Aspirin at 9 minutes. Melting Order

Compound

Formula

Melting point

Boiling point

1

Paraffin Wax

C31H64

99 °F/ 37 °C

698 °F/ 370 °C

2

Aspirin

C9H8O4

275°F/ 135.0°C

284°F/ 140°C

(Did not melt)

Sodium Thiosulfate

Na2S2O3

118.94°F / 48.3 °C

212°F / 100°C

(Did not melt)

Zinc

Zn

787.1°F/ 419.5°C

1664°F/907°C

(Did not melt)

Epsom salts

MgSO4

1124°C (anhydrous)

N/A

(Did not melt)

Sodium Chloride

NaCl

1474°F/ 800.7°C

2575°F/ 1465°C

(Did not melt)

Copper

Cu

1981°F/ 1083°C

4703°F/ 2595°C

Part C - Conductivity: Compound

Electrical Conductivity (V) (air)

Electrical Conductivity (V) (water)

Thiosulfate

0

1.84

Sodium Chloride

0

2.2

Epsom Salt

0

2

Aspirin

0

1.3

Zinc

3

(Not soluble in water)

Copper

3

(Not soluble in water)

Paraffin Wax

0

(Not soluble in water)

Part D – Internet Research Group

Compound

Formula

Melting point

Boiling point

Paraffin wax

C31H64

99 °F/ 37 °C

698 °F/ 370 °C

Epsom salts

MgSO4

200°C (monohydrate)/1124 °C (anhydrous)

N/A

Sodium Chloride

NaCl

1474°F/ 800.7°C

2575°F/ 1465°C

Copper

Cu

1981°F/ 1083°C

4703°F/ 2595°C

a

b

Zinc

Zn

787.1°F/ 419.5°C

1664°F/907°C

Aspirin

C9H8O4

275°F/ 135.0°C

284°F/ 140°C

Magnesium Oxide

MgO

5072 ° F / 2825°C

6512 ° F / 3600

Calcium Bromide

CaBr2

1346° F / 730 °C

3299°F / 1815°C

Tungsten

W

6170 ° F / 3410

10701°F / 5900

Iron

Fe

2800 °F / 1538 °C

5182 °F / 2862 °C

Calcium Hydroxide

Ca(OH)2

1,076 °F / 580 °C

5162°F / 2850°C

Octane

C8H18

−69.8 °F / −56.6 °C

258.9 °F / 126.1 °C

Cobalt

Co

2723°F / 1495°C

5301°F / 2927°C

Carbon Tetrachloride

CCl4

-9.26°F / -22.92 °C

170.1° F / 76.72 °C

Acetylene

C2H2

−113.4°F / -80.8 °C

-119.2°F / -84 °C

c

d

e

f

g

Sites Used: 1. Geoff. (n.d.). What's in your drinking water? Retrieved October 2, 2019, from http://freshlysqueezedwater.org.uk/waterarticle_watercontent.php. 2. Home. (n.d.). Retrieved October 2, 2019, from https://www.uswatersystems.com/deionized-water-vs-distilled-water. 3. Water Treatment Solutions. (n.d.). Retrieved October 2, 2019, from https://www.lenntech.com/applications/ultrapure/conductivity/water-conductivity.htm. 4. Why metals are good conductors of electricity? Socratic. (2014, March 23). Retrieved October 2, 2019, from https://socratic.org/questions/why-metals-are-good-conductors-ofelectricity....