C3.1 Flashcards
what is a diatomic molecule
two atoms COVALENTLY bonded together.
what is the law of conservation of mass
atoms cannot be created or destroyed by chemical reactions. They are joined in a different way, so the total mass stays the same during the chemical reaction.
closed system
container where no substances can enter or leave during the reaction.
formula to calculate mass
mass of reactant 1 + mass of reactant 2 = mass of product
why is a balanced equation helpful
- tells us the relative amounts of each substance involved
- shows how the atoms are arranged in the reaction
when doing half equations, what should you consider for anode
if the negative ion is a halide ion, it will be produced
BUT if it is not a halide ion, oxygen and water will be produced
REMEBER THIS EWUATION FOR IT :
4OH- ——> 2H2O + O2 + 4e-
when doing half equations, what should you consider for cathode
compare the positive ion to hydrogen on the reactivity series.
if above hydrogen, hydrogen is produced
if below hydrogen, that thing is produced (normally j gold )
how to make an ionic equation
find all the substances that are aq
only split those - based on charge
such as Hcl would be H+ + Cl-
leave the non aq ones alone
after cancel out the same ones on either side and rewrite REMEMBER WITH symbols
what are spectator ions
in the mixture but don’t take part in the reaction
Avogadro constant
6.02 x 10^23 mol
mole formula
n = m/mr
what is a limiting reactant
something that is completely consumed in a chemical reaction
stoichiometry
when you find out ratio and balance the equation by finding out n=m/mr for the substances on one side
