What atoms do covalent bonds occur between?
Metal and non-metal atoms
A single covalent bond is formed when two atoms share one pair of electrons
How many electrons are shared when a double bond is formed?
What is each atom aiming to do when sharing it's electrons?
Get a full outer shell
Lose all of its neutrons
Give away all of it's electrons to other elements
Share with all it's friends to make the world a happier place
What are the properties of a simple covalent molecule? (2)
Weak forces between the molecules
Strong covalent bonds between atoms
Weak covalent bonds between atoms
Strong forces between the molecules
Simple covalent molecules have high melting and boiling points and can conduct electricity
What makes the giant molecule different to a simple molecule?
Many of the atoms in a giant molecule are joined together covalently throughout the whole giant molecule structure
There are more electrons in the atoms of the giant molecules which makes them negatively charged and able to conduct electricity
Giant molecules have high boiling and melting points, simple molecules have low ones
A simple molecule is made by breaking the atoms apart, a giant molecule is made by connecting atoms together manually
Graphite is used to make
Cars and airplanes
Electrodes and lubricants
Roofs of houses and flooring
Soles of shoes and hair clips
Does graphite have weak forces of attraction between its layers or strong?
What methods can you use to test different compounds?
Melting them using a bunsen burner
Placing electrodes into a sample of the substance to see if it conducts electricity as a solid, liquid or aqueous solution
Timing how long it takes the substance to dissolve in water
What is the definition of immiscible?
When two liquids are mixed together and form distinct separate layers
When liquids are mixed together and stay mixed together
When liquids turn to carbon dioxide when placed together
When liquids turn to a gas when they have been placed in a freezer
Miscible is when liquids are mixed together and they stay mixed together
How would you separate miscible liquids?
By using distillation or fractional distillation
By shaking them around
By using a separating tunnel
By placing them in a water bath
Once oxygen has been separated from liquid air by fractional distillation what can we use it for?
To help young children breath better
To help freeze food quickly
To put back into the air
What is chromatography used for?
To separate dissolved dyes used in food colourings
To check foods for additives, contaminants and other substances
To separate traces of chemicals in fires
To identify drugs
To test our blood pressure
To test for animal faeces
How do we work out the Rf value of a substance?
Distance moved by soluble substance / Distance moved by solvent
Distance moved by solvent / Distance moved by soluble substance
Distance moved by soluble substance x Distance moved by solvent
Distance moved by soluble substance + Distance moved by solvent