Topic 3 Flashcards
What is a covalent bond
This is a shard pair of electrons between two non metals
What are the properties of a simple covalent bond
The covalent bonds are very strong however the forces of attraction between molecules is very weak. This means the melting and boiling points are very low and are easily parted from each other.
What are the properties of giant covalent substances and why
All atoms are bonded to each other by strong covalent bonds this means they have very high melting points but they do not conduct electricity they are usually insoluble in water
Why does graphite conduct electricity even though it’s a giant covalent molecular structure
Each carbon atoms only forms three covalent bonds creating sheeting of carbon atoms which can slide over each other. As only three of four outer electrons are used in bond there are lots of delocalised electrons. These electrons conduct electricity
What does miscible mean
Liquids that mix together and there is no distinction between them
When shaken which will fall to the bottom water or oil
Water as it is more dense These liquids are I miscible
How can miscible liquids be separated
Through fractional distillation,
What is chromatography used for
To separate out the mixture and see what’s in it
What is an Rf value and how to calculate it
It is the ratio between the distance travelled by the dissolved substance and the distance travelled by the solvent. To calculate is divide the distance sptravelled by the substance by the distance travelled by the solvent.
