Structure and properties Flashcards
Why do ionic solids have high melting points and what does this mean
They have strong electrostatic forces of attraction and are solids at room temperature. A lot of energy is needed to overcome these forces.
Why can ionic substance conduct electricity when in liquid state
The ions are free to move
Give the properties of a molecule covalently bonded
Have intermolecular forces and are weak. Low melting/boiling points. They have no overall charge so cannot conduct electricity
What is a giant covalent structure
Called a macromolecule, needs a lot of energy to break down and have very high boiling points
Give the structure of a diamond
GCS made of carbon
Each carbon is covalently bonded to 4 other carbon atoms. This make it hard and transparent.
Give the structure of graphite
GCS made of carbon
The atoms are covalently bonded to 3 other carbon atoms. Layers are formed and there are no bonds between the layers (intramolecular bonds) so they slide over and allow you to write with it as it’s slippery.
Give the structure of a fullerene
GCS made of carbon
Hexagonal rings of carbon atoms. Differing numbers of bonds. Some of them are nano-sized.
What is a shape memory alloy
A mixture of metals that hen moulded and then reheated it returns to it’s original shape. Such at nitinol for dental braces.
What’s the difference between a thermosetting and a thermosoftening plastic
Thermosetting do not melt or soften when we heat them whereas thermosoftening plastics do. Plug sockets are thermosetting and most plastics with poly in front are thermosoftening. Thermosoftening have weaker forces so it can be remoulded but the intermolecular forces help it to reset.
What is nanoscience
Teeny science. A nanometre is one billionth of a metre. They have a large surface area.
What is nanotechnology
Uses nanoparticles for products such as catalysts, coatings, cosmetics (sun cream and deodorants).
Why do product with nanoparticles need to be rigorously tested?
Unpredictable results as to what effect they could have on the environment and our health if they enter the air/our bodies. More research needs to be done.
