Chapter 2: Structure and properties Flashcards
What are the features of simple molecules?
Low boiling and melting points
Held together by covalent bonds
No over all electric charge
Forces inside a molecule are called
Intra molecular forces
Forces between molecules are called
Inter molecular forces
Why are simple molecules usually gaseous?
The force of attraction between molecules is not strong, as they are small.
What are the structures formed by ionic bonding called?
A giant ionic lattice
What are the features of Ionic compounds?
High melting points
High boiling points
Three examples of Covalent Structures
Diamond, Silicone Dioxide and Graphite
What makes Graphite weak?
It is arranged in layers which can slide over each other.
Why can graphite conduct electricity and heat?
Because each atom is only bonded to three others (whereas it can bond to four), it has a de-localized electron
How are the atoms arranged in pure metals?
Rows and columns. This means that they can be easily bent.
What is an alloy?
A mixture of metals
Why are alloys generally harder than pure metals?
The other atoms disrupt the regular structure of the metal
How is LDPE made from Poly ethene molecules?
High pressure + oxygen
How is HDPE made from Poly ethene molecules?
Higher pressure + oxygen
Why is HDPE stronger than LDPE?
HDPE is compact which means the inter molecular forces are stronger.
