C3.1 Flashcards
What can the formulae of metals be written as
Metals are always written empirically as they exist in giant metallic lattices
What do the non-metals in group 0 exist as
They exist as individual atoms, attracted to each other by weak intermolecular forces.
What is a diatomic molecule
A diatomic molecule contains two atoms covalently bonded. An example is CL2.
What do phosphorus and sulphur exist as
P4 and S8
What does the molecular formula for a simple covalent structure contain
.The symbols for each element it contains
.The number of atoms of each element in one of its molecule
What do the metals in group 1,2,3 produce ions of
They produce positive ions of which the charge is the same number as their group.
What ions do transitional metals form
They form 2+ ions.
What do metals in group 5,6,7 produce ions of
They produce negative ions in which the number of charges = 8 - group number
Formula of different compound ions
ammonium NH4+
silver Ag+
Barium Ba2+
Copper (||) Cu2+
Iron (||) Fe2+
Lead (||) Pb2+
Zinc Zn2+
Aluminium Al3+
Iron Fe3+
Hydroxide OH-
Nitrate NO3-
Carbonate CO3 2-
Sulfate SO4 2-
Law of conservation of mass
Atoms can’t be created or destroyed in a chemical reaction.
How can you investigate the law of conservation of mass
You can investigate conservation of mass in a closed system
. a beaker of reactants in a solution where the products are not gases
. A flask attached to a gas syringe to stop products in the gas state from escaping
Why would there be a decrease in mass in a reaction
Substances can leave or enter the reaction mixture in a non-enclosed system. This usually happens when the reaction involves a gas. For example if a gas is produced it will escape causing a decrease in mass. It can also appear to go up if reacts with air.
What does a balanced equation show
.How atoms are rearranged in a reaction
.The relative amount of each substance
When is an an equation balanced
When there an equal number of atoms of each element on both side of the equation.
Different state symbols
(s) - solid
(l) - liquid
(aq) - aqueous
(g) - gas
What is a half equation
A half equation is a model for the change that happens to one reactant in a chemical reaction.
Example of a half equation
Na -> Na+ + e-
What must you do in half equations
Balance the charges
What does an ionic equation show
It shows the ions present in a reaction mixture. It usually also includes the formulae of any ionic substances present.
What are spectator ions
They are in the reaction mixture but don’t take part in the reaction.
What is the mole
The mole is the amount of any substance that contains the same number of entities as there are in 12g of carbon -12 atoms.
Mole formula
Mole = Mass/molar mass (mr)
