C2.2 Properties & Uses of Substances Flashcards Preview

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Flashcards in C2.2 Properties & Uses of Substances Deck (5):
1

Do electrons, protons, or neutrons define the element?

Protons
If you change the amount of protons, you change the element

2

What is LDPE and what is it used for?

Low density poly ethene is used for plastic bags

- made at 100 -300 degrees at pressure of 1500 - 3000 atm
- branching from the main chains allows strength and stretch
-low density

3

What is HDPE and what is it used for?

High density poly ethene is used for plastic garden chairs
-made at 300 degrees at a 1 atm pressure
-Aluminium based metal oxide catalyst used
- chains very close -> high denisity and melting point

4

What is thermosoftening?

Thermosoftening polymers soften when heated and can be reshaped but harden again when cooled

eg LDPE

5

What is thermosetting?

Thermosetting polymers harden for good once cool

eg HDPE