Principle Of Chemistry (States Of Matter, Atoms, Separating, Bonding) Flashcards
The state of matter of an object depends on what
The forces of attraction between the particles
What are molcules
Groups of atom
What is an element
One type of atom
What is a compound
Atoms chemically bonded together
What is a mixture
Atoms mixed together - can be easily separated
Relative mass of a proton
1
Relative mass of a neutron
1
Relative mass of an electron
1/2000
Relative charge of a proton
+1
Relative charge of a neutron
0
Relative charge of an electron
-1
What is the atomic number
Number of protons (bottom number)
What is the mass number
Number of protons + neutrons
What is an isotope
Atoms with the same number of protons but a different number of neutrons
What is relative atomic mass
A measure of the mass of one atom of an element
What is the periodic table arranged in order of
In order of atomic number
How do you find the number of outer electrons
Look at the group
What is oxidation
The loss of electrons
What is reduction
The gain of electrons
When an element gains ions it becomes __ve. When an element loses electrons they become __ve. When these meet, they attract to form what?
+ve
-ve
Ionic compounds
Ionic compounds have _____ melting and boiling points
High
Why do ionic compounds have high melting and boiling points
Because of strong electrostatic forces between oppositely charged ions
A lattice of 2+ and 2- ions will have _________ forces of attraction than a lattice of 1+ and 1- ions
Stronger
Lattices made up of higher charge ions will have __________ melting and boiling points
Higher
What is an ionic crystal
A giant 3d lattice held together by the attraction between oppositely charged ions
What is covalent bonding
Sharing electrons
What is the attraction between atoms in covalent bonding
There’s a strong attraction between the shared electrons and the nuclei of the atoms involved
What is a simple molecular substance
A liquid or gas / or a solid with a very low melting point
Describe the structure of a simple molecular substance
The atoms within the molecule are held together by very strong coalent bonds. But the forces of attraction between the molecules themselves are very weak (weak intermolecular forces)
Giant covalent bondings have ______ melting and boiling points
High
Describe the structure of giant covalent structures
Atoms bonded together by strong covalent bonds. There are many of these bonds… therefore it takes a lot of energy to break the, hence, high melting and boiling points
Giant covalent structures are __________ in water, and they ______ conduct electricity. Examples are ___________ and __________
Insoluble in water
Don’t conduct electrcicty
Diamond and graphite
Describe a metal
A giant structure of positive ions surrounded by a sea of delocalised electrons
When do ionic compounds conduct electricity
When molten or in solution (since the ions are free to move (and carry current))
Why can’t covalent compounds conduct electricity
Because they don’t have any ions
Why are metals good conductors of electricity and heat
Because they have free electrons
How are metals malleable
Because the layers of atoms can slide over each other
What is diamond used for
Cutting
What is graphite used for
Lubricants
Describe the structure of diamond
Each carbon atom forms 4 covalent bonds in a very rigid giant covalent structure
Describe the structure of graphite
Each carbon atom only forms 3 covalent bonds, creating layers which are free to slide over each other
What is filtration used to separate
An insoluble solid from a liquid
What is crystallisation used to separate
A soluble solid from a solution
What is filtration followed by crystallisation is used to separate
Rock salt
What is distillation used to separate
A liquid from a solution
Describe filtration
The solid gets stuck on the filter paper, thus, it’s separated from the liquid
Describe crystallisation
- Pour solution in evaporating dish
- Heat. The solvent will evaporate and crystals will form
- Leave crystals in a warm place for the rest of the solvent to evaporate
- Dry (in a drying oven)
What is rock salt
A mixture of salt and sand
Name the 4 steps in separating rock salt
- Grinding
- Dissolving
- Filtering
- Crystallisation
Describe simple distillation
The solution is heated. The part that has the lowest boiling point evaporates. The vapour is then cooled, condenses and is collected. The rest of the solution is left in the flask.
