Quantative chemistry Flashcards
How do we calculate relative formula mass of a compound?
Add together the relative atomic masses of of all the elements in the compound
What are three examples of reactions in which mass changes?
Burning of wood
Zinc + hydrochloric acid
Corrosion of metals
Why is it that in chemical reactions substances may seem to lose or gain mass?
Normally one of the reactants or products is a gas and can escape into the surrounding environment.
Why is it that when metals corrode the overall mass of the reaction will appear to increased?
Oxygen atoms from the atmosphere have been added to the metal
Chemical equations must be balanced …
to make sure that there are the same number of of atoms of each element before and after a reaction
The molecular formula shows…
The actual amount of atoms which make up a molecule
The empirical formula shows…
the simplest ratio of atoms which make up a molecule
What are moles?
A measurement of chemical amounts
What is the value of Avogadro Constant
6.02 x 10•23
The relative formula mass of a substance is…
equal to the mass of 1 mole of that substance
The reactant this is completely used up is called?
The limiting reactant
