What type of bonding is present in a given substance?

Background Research

Risk Assessment

Variables

What are the types of bonding? There are three main types of bonding; ionic, covalent, and metallic. Ionic bonds are formed between metals and non-metals, covalent bonds are formed between non-metals and metallic bonds are formed between metals.

Properties of bonds Covalent bonds have:

  • low melting points
  • Low boiling point
  • Do not conduct electricity in the solid, molten or aqueous state.
  • Is not solid at room temperature

Properties of bonds Ionic bonds have:

  • High melting point
  • High boiling point
  • Electrical Conductivity when in molten or aqueous state
  • Hard but Brittle
  • Often soluble in water

Properties of bonds Metallic Bonds have:

  • High melting point
  • High boiling point
  • Good conductors of heat
  • Good conductors of Electricity
  • Malleable
  • Ductile
  • Poor solubility

For metallic bonds: The delocalised electrons are able to move
freely in the 'sea'. These mobile electrons are
therefore able to carry charge or heat energy. Molten ionic compounds are good conductors of electricity due to the ability of ions to move freely within the substance. Covalent Bonds do not conduct electricity in the soild, molten, or aqueous state.

When testing the malleability and how ductile a substance is, a hammer or other tools may be used. For safety reasons, safety glasses should be worn, as well as a lab coat and gloves depending on the substance.

Examples of methods to find a substance

Care should be taken when handling unknown substances and chemicals, as well as when using lab equipment such as Bunsen burners.

Instead of smelling unknown substances, waft them

Disposal of substances

Substances such as oil should not be poured down the drain. Instead, they can be stored in containers or disposed of in garden composts.

Substances should not be disposed randomly of if they are unknown.

Dependent VariableA dependent variable is what is being measured. In this case that is the type of bonding presnet in the given substance

Controlled variables All of the substances will be tested and identified in the same environment with the same tempertaure. The testing and method will be carried out by the same person consistenly.

Independent Variable is the different substances

Steps to take when attempting to identify an unknown substance: First look at its physical appearance.

  • What does it look like?
  • What does it smell like?
  • Is it slippery or not?
  • What state is it? Is it a solid or liquid?

For example, for graphite, the first test to be conducted is to touch. Scribble it on a piece of white paper and see if it leaves a mark. Graphite can be tested by using an electrical conductivity kit, if the light is glowing then it is graphite. From this information we can infer to what type of bonding is present.

Methods of identification:

  • Electrical conductivity kits
  • Appearence
  • Strength, Malleability and how ductile it is
  • Is is it brittle?
  • Melting or boiling points
  • Bunsen Burner

Precautions and Safety:

  • Always wear gloves when handling chemicals. - Always wear appropriate clothing: chemically resisant lab coats and no exposed feet
  • Confine long hair and loose clothing
  • Use chemicals only as directed and for their intended purpose.

Emergency Procedures:

  • Know where the nearest emergency eyewash is and how to use it.
  • Know where the exits are from the classroom in case of an emergency.
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Another example is sand which can be demonstrated in its appearance and it is grainy texture. Sand has a rough texture which can be felt through gloves. A hammer can be used to show that sand will not be changed with a hammer. The electrical conductivity kit can be used, although sand does not conduct electricity. Placing sand in water will demonstrate that sand has a covalent network structure.

Safely dispose of all chemicals and substances. Seek guidance from teachers if needed.

What is the aim of this practical? In this experiment the aim is to identify the type of bonding present in given substances. Using different equiptment and techinique, the type of bonding will be identified through practical knowledge of physical properties of covalent, ionic and metallic compunds.

chem

Link to controlled variable table here: https://docs.google.com/document/d/1KZIzya0faeaomlqrmhVjL8HLOzU701vPqUtjuh1_ZWk/edit

Possible Errors

Random errors: possibe random errors include observational errors, eg, reading the measurement wrong or recording the wrong details.

Systematic errors: One example of an systematic error is a electrical conductivity kit which constantly gives the wrong readings.

Limitations: - One limitation in the experiment may be running out of time to conduct various tests on each of the unknown substances. - The equipment required may not be available

Student method

To identify what type of bonding is present in these given substances, the following procedures will be followed: First, the physical appearance and properties of the substance will be investigated. Answering the question about what the given substance smells or feels like will help to understand and narrow down the options of what it could be.


An electrical conductivity kit can be used to test the conductivity of the chosen substance. Covalent bonds do not conduct electricity, while metallic and ionic bonds do, depending on their state.


Using a hammer or other equipment, the chemical can be tested for malleability and how ductile it is, as well as if it is brittle or not. This helps to demonstrate what type of bonding is occuring. A part of the substance can be heated up using a Bunsen burner to test and investigate its melting and boiling points.

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