Formula and Equations Flashcards
Compound
Substance formed when two or more different elements are chemically combined
How can you tell a compound contains two elements?
It ends with -ide
How can you tell a compound contains oxygen?
It ends with -ate
What can be found using the valency?
The ratio for any two atoms reacting and forming a compound
What is the valency of group I?
1
What is the valency of group II?
2
What is the valency of group III?
3
What is the valency of group IV?
4
What is the valency of group V?
3
What is the valency of group VI?
2
What is the valency of group VII?
1
What is the valency of group 0/8?
0
How do you find the valency of transition metals?
Look at data leaflet - back of periodic table
What is valency?
- valency is the combining power of an element
- elements in the same group of the periodic table have the same valency
- the valency of an element is related to how many electrons are in the outer shell
What is a simple compound?
Compound containing only two elements
How do you write the formulae of compounds?
- write the symbols
- write the valencies in pencil beside the symbols
- swap the valencies
- find the simplest ratio
What are molecular ions?
- charged particles containing more than one atom
- compounds containing groups of atoms
What are compounds containing three or more elements
- groups of atoms - back of periodic table
- e.g copper sulfate - made up of copper, sulfur and oxygen - sulfate group
Where are lists of common groups of atoms found?
On the data leaflet
How is the valency found in groups of atoms?
The valency is equal to the charge on the ion
e.g sulfate group - formula SO4 and valency of 2 - written as SO4 2- on data leaflet
Why are brackets used in compounds?
If the compound contains two or more of a particular group then brackets must be used
pieces of information in a balanced symbol equation
- formulae of reactants and products
- amount or number of particles of each chemical reacting or products forming
reactant
Chemical at start
products
Particles at end of experiment
How is an equation balanced?
step one: from known word equation write down formula of reactants and products
step two: count atoms on both sides of equation
step three: if number of each type of atom on either side is not the same - balancing the equation is necessary
step four: put big numbers before of formula which contains atoms that do not balance - never change small numbers in formula
step five: keep balancing until atoms on each side of equation are the same
Why do we balance equations in pencil?
You often have to change numbers put in first
Diatomic molecules
- diatomic - two atoms covalently bonded in molecule
- molecule - particle that consists of two or more covalently bonded atoms
Molecule
particle that consists of two or more covalently bonded atoms
HCl
Hydrochloric acid
Nitric acid
HNO3
Sulfuric acid
H2 SO4
relative atomic mass (Ar / RAM)
- term used for elements
- Ar = mass number (use periodic table)
relative formula mass (Mr / RFM)
- sometimes referred to as relative molecular mass (RMM)
- used for compounds
- sum of the relative atomic mass of each atom in one molecule of a compound
Aqueous
Dissolved in water
What is the valency of an element related to?
the valency of an element is related to how many electrons are in the outer shell
