chemistry

?
what does covalent bonding happen between?
Non-metals
1 of 19
what happens in covenant bonding?
sharing of electrons
2 of 19
list properties of simple covalent molecules
Low melting points, low boiling points, don't conduct electricity, usually gas or liquid at room temp
3 of 19
List properties of giant covenant structures
High melting points, high boiling points,don't conduct electricity.
4 of 19
Name two giant covalent structures made out of carbon
Diamond and graphite
5 of 19
How many bonds does diamond make?
3
6 of 19
How many bands does graphite make?
4
7 of 19
Compare diamond and graphite properties.
Diamond is hard, strong, has high m & b points, and cant conduct electricity because it has no free electrons. But graphite has layers that slide over eachother other so it is soft. It also has free electrons between layers so can conduct electricity.
8 of 19
Why are pure metals soft?
Because it has layers that slide over each other
9 of 19
Can pure metals conduct electricity? why/why not?
yes because they have free electrons
10 of 19
What is an alloy?
An alloy is a mixture of two elements, one of which is a metal.
11 of 19
Why are alloys harder than pure metals?
They contain atoms of different sizes, which distorts the regular arrangements of atoms. This makes it more difficult for the layers to slide over each other, so alloys are harder than the pure metal which has layers that can easily slide.
12 of 19
What is a shape memory alloy?
Shape memory alloys can return to their original shape after being bent or twisted.
13 of 19
what is an example of a shape memory alloy? what is it made from? what is it used for?
Nitinol. Made fromm nickel and titanium, used for teeth braces.
14 of 19
List properties of thermosoftening polymers
They soften when heated and can be shaped when hot. The shape will harden when its cooled, but can be reshaped when heated up again.
15 of 19
Name an example of a thermosoftening polymer
Poly(ethene)
16 of 19
List properties of thermosetting polymers
Once moulded, they don't soften when heated, and they cannot be reshaped.
17 of 19
Why are thermosetting polymers flexible?
Its tangled polymer chains can uncoil and slide past each other, making it a flexible material.
18 of 19
Why aren't thermosetting polymers flexible?
Its polymer chains are joined together by cross-links, so they cannot slide past each other easily.
19 of 19

Other cards in this set

Card 2

Front

what happens in covenant bonding?

Back

sharing of electrons

Card 3

Front

list properties of simple covalent molecules

Back

Preview of the front of card 3

Card 4

Front

List properties of giant covenant structures

Back

Preview of the front of card 4

Card 5

Front

Name two giant covalent structures made out of carbon

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Science resources:

See all Science resources »See all Polymers resources »