C2 Quiz

Melting Point is....

Tensile strength is....

Choose 3 examples of natural materials

What is meant by the word 'polymer'?

What are hydrocarbons?

Crude oil is separated by a process called fractional [blank_start]distillation[blank_end]. Crude oil is heated to around 400 degrees celsius to turn all the hydrocarbons to gases. The gas is then passed into a fractional distillation [blank_start]column[blank_end] where the gases rise up cool and [blank_start]condense[blank_end] to liquid at their boiling points. Some have [blank_start]high[blank_end] boiling points so condense lower down, while those with lower boiling points [blank_start]rise[blank_end] up the column. Some stay as [blank_start]gases[blank_end] even at the top of the column. Each substance is a mixture of [blank_start]hydrocarbons[blank_end] with similar boiling points called a fraction. The hydrocarbons of each fraction have [blank_start]similar[blank_end] boiling points as the molecules in that fraction are all a similar size - they have a similar number of [blank_start]carbon[blank_end] and hydrogen atoms. There are [blank_start]attractive[blank_end] forces between molecules which hold them together. Force is needed to separate these molecules. When heated, the molecules gain [blank_start]energy[blank_end] until they have enough energy to overcome the forces holding them together and the molecules become a [blank_start]gas[blank_end].

Polymerisation is the process of making a polymer.

What notation would be used to express a polymer of polyethene?

All polymers are chemically synthesised.

An important reason why [blank_start]synthetic[blank_end] polymers have been chosen for a purpose is because they are [blank_start]cheaper[blank_end] and available in larger quantities than the natural material they replace. This is why [blank_start]nylon[blank_end] replaced silk and [blank_start]wool[blank_end] for stockings in the 1940s. Synthetic polymers have many other properties that make them [blank_start]useful[blank_end] and also their properties can be [blank_start]adjusted[blank_end] to make them suit the job they have to do.

There is a [blank_start]force[blank_end] between polymer [blank_start]molecules[blank_end] that pulls them together. The [blank_start]closer[blank_end] the molecules are to each other, the stronger the force. Polymers with a [blank_start]larger[blank_end] force between their molecules melt at [blank_start]higher[blank_end] temperatures.

What does it mean to say a material is highly 'crystalline'?

What effect do plasticisers have on a polymer?

Cross-linked polymers are thermosetting plastics.

What size range does nanotechnology involve?

Why do nanoparticles of gold or other materials act as good catalysts?

Nanoparticles have been used in products such as [blank_start]cosmetics[blank_end] and sunscreens, and tests have shown that they are not [blank_start]harmful[blank_end] to the skin. However, the nanoparticles are so small that they can slip through tiny [blank_start]pores[blank_end] in the skin and be [blank_start]absorbed[blank_end] by the blood where they could be carried to the organs in the body. It is not known if these substances may be harmful to tissues. One fear is that breathing [blank_start]carbon[blank_end] nanotubes into the lungs to cause diseases in the way that the tiny fibres of [blank_start]asbestos[blank_end] do. We need to find out how [blank_start]hazardous[blank_end] nanoparticles are so that we can assess whether they pose too great a risk to health. Some people think that as nanoparticles occur [blank_start]naturally[blank_end] they are no danger as we have evolved to live with them. Others disagree as scientists are now making [blank_start]synthetic[blank_end] nanoparticles that have new and [blank_start]unexpected[blank_end] properties.