GCSE Chemistry - What is a Polymer? Polymers / Monomers / Their Properties Explained #23

Summary

This video introduces polymers, explaining their structure and properties. Polymers are large molecules made of repeating units called monomers, like propene in polypropylene. The video covers how to identify polymers by their repeating units and how to represent them with the letter 'n'. It also explains the difference between covalent bonds within polymer molecules and the weaker intermolecular forces between them, which determine their melting and boiling points. Due to these forces, polymers are solid at room temperature. The video briefly touches on addition and condensation polymers, which will be explored further in future content.

Takeaways

• 😀 Polymers are large molecules made up of smaller repeating units called monomers.
• 😀 Polypropylene is an example of a polymer, formed from monomers like propene (C3H6).
• 😀 A polymer's structure consists of a long chain of repeating monomers connected by covalent bonds.
• 😀 To identify a polymer, you can spot the repeating monomer within the molecule.
• 😀 The repeating monomer of a polymer can be drawn separately and denoted with the letter 'n' to represent the number of repeating units.
• 😀 To write a polymer reaction, we typically use the repeating unit and the letter 'n' rather than drawing out the full polymer chain.
• 😀 When drawing polymer chains, curved brackets are used to show the repeating units and the bonds extending from them.
• 😀 Polymers have strong covalent bonds within the molecules, but their melting and boiling points are determined by weaker intermolecular forces between the molecules.
• 😀 Intermolecular forces in polymers are weaker than covalent or ionic bonds but still require significant energy to break due to the long chains and high surface area of the polymers.
• 😀 Polymers typically have higher melting and boiling points than simple molecular substances, like oxygen or chlorine, but lower than giant covalent or ionic structures, like diamond or sodium chloride.
• 😀 Polymers are generally solid at room temperature because of the strong intermolecular forces between their long chains, despite having lower melting and boiling points compared to other substances.
• 😀 Two main types of polymers are addition polymers and condensation polymers, which will be explored in future videos.

Q & A

What are polymers made of?

Polymers are made up of long chains of smaller units called monomers, which are repeated to form large molecules.

What is an example of a polymer mentioned in the video?

An example of a polymer mentioned is polypropylene, which is a common polymer used in plastic.

How can you tell if a molecule is a polymer?

You can tell a molecule is a polymer by identifying a repeating monomer unit in its structure.

What does the 'n' represent in the drawing of a polymer?

'n' represents the number of repeating monomer units in the polymer chain, indicating how many times the unit repeats in the overall molecule.

What is the formula for the monomer used in polypropylene?

The formula for the monomer used in polypropylene is C3H6, which is called propene.

What is the significance of the curved brackets when drawing repeating units?

Curved brackets are used to show the repeating unit in a polymer, with bonds extending from the brackets to represent the covalent bonds between monomers.

Why do polymers have relatively high melting and boiling points compared to simple molecular substances?

Polymers have higher melting and boiling points because they have large molecules with high surface area, leading to strong intermolecular forces, although weaker than covalent or ionic bonds.

What is the difference between the bonds in a polymer and those in diamond or sodium chloride?

In a polymer, the bonds within the molecule are covalent, but the forces between individual polymer molecules are weaker intermolecular forces. In contrast, diamond has very strong covalent bonds, and sodium chloride has strong ionic bonds.

What are the intermolecular forces in polymers responsible for?

The intermolecular forces in polymers are responsible for determining their melting and boiling points. These forces are weaker than covalent bonds but still require significant energy to break because of the polymer's large size.

What are the two main types of polymers mentioned in the video?

The two main types of polymers mentioned are addition polymers and condensation polymers, which will be discussed in other videos.