Macromolecules Flashcards
What is a macromolecule?
A very large molecule made up of a regular lattice of covalently bonded atoms.
What is an allotrope?
Different structural forms of the same element in the same physical state. Have a different arrangement of atoms.
What kinds of bonds exist in between atoms diamond, graphite and silica?
Covalent bonds between the atoms
How many bonds does one carbon atom in diamond make?
4
How many bonds does one carbon atom in graphite make?
3
What is the structure of diamond?
Giant covalent structure / giat molecular structure / macromolecular
Describe the structure of graphite
Atoms are in hexagonal layers arranged on top of each other. Each hexagon layer is a two dimensional giant molecule
What exists between the hexagonal layers of graphite?
Intermolecular forces of attraction
Why is diamond solid at room temperature?
Millions of strong covalent bonds.
Why does diamond have a high melting point?
Covalent bonds are very strong, A lot of energy is needed to break them
What makes diamond hard and strong?
Strong covalent bonds
Why doesn’t diamond conduct electricity?
Has no moving electrons as all the outer electrons of each carbon atom are involved in bonding.
Has no moving ions
Why isn’t diamond soluble in water?
Particles aren’t charged. Water molecules aren’t attracted to them
Why is graphite a solid at room temperature?
It has millions of strong covalent bonds.
Graphite has a high melting point because?
Strong covalent bonds need a lot of energy to break them.
Why is graphite relatively soft in comparison to diamond?
Individual layers are held together by weak intermolecular forces of attraction, not covalent bonds. Layers are therefore free to slide over one another.
Why does graphite conduct electricity and heat?
Each carbon atom is covalently bonded to only three other carbon atoms. This means that each has one delocalised electron that isn’t involved in bonding and can move around freely.
Why is graphite used to make pencils?
Layers are soft and can slide onto the paper
Why is graphite used in lubricants?
Layers can slide over each other(lubricants make moving parts move smoothly).
Graphite conducts electricity. Where can it therefore be used?
Batteries, solar panels and electrodes
What are the elements found in silica?
Silicon, oxygen
What is the structure of silica?
Giant molecular structure
Why is silica a solid at room temperature?
Has millions of strong covalent bonds.
Silica has a high melting and boiling point because…
A lot of energy is needed to break the strong covalent bonds.
Why doesn’t silica conduct electricity?
No moving electrons to carry an electric charge. No moving ions
Why isn’t silica soluble in water?
Particles aren’t charged. Water molecules aren’t attracted to them.
What are the uses of silica?
making glass, making concrete and in construction (it is very strong) , anti caking agents, pharmaceuticals.
Why is diamond used in jewellery?
It reflects and refracts light very well and is durable
Why is diamond used in cutting tools such as glass cutters?
It is very hard and strong due to the strong covalent bonds
How can diamond be used in medicine?
Surgical instruments can be coated in diamond and used for delicate operations such as on the eye
What is each oxygen atom in silica bonded to?
Each oxygen atom is covalently bonded to two silicon atoms
What is each silicon atom in silica bonded to?
Each silicon atom is covalently bonded to 4 oxygen atoms.
