Flashcards in C2.2 Properties & Uses of Substances Deck (5):
Do electrons, protons, or neutrons define the element?
If you change the amount of protons, you change the element
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
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
What is thermosoftening?
Thermosoftening polymers soften when heated and can be reshaped but harden again when cooled