STOICHIOMETRY (1) !!

What is stoichiometry?
stochio=Greek for element
metry=measurement

Stoichiometry is a branch of chemistry that deals with the quantitative analysis of chemical reactions and is about measuring the amounts of the elements and compounds involved in a reaction.

It is the study of the relationship between the amount of reactants uesd in a chemical reaction and the amounts of products produced by the reaction.

Consider the chemical reaction:
4NH3+5O2→6H2O=4NO
with stoichiometry, we find out:
4:5:6:4
do more than just multiply atoms
4:5:6:4
are what we call a mole ratio.

Balanced chemical equations are required.
It tells us the ratio of the molecules or moles of the substances in a chemical reaction.

ex
For the equation: Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g)
a) How many atomes of Zn are needed to produce 1 molecule of Hydrogen?
1 molecule H×1atom Zn/1molecule H=1atom Zn

b)How many moles of HCl are needed to produce 0.452 moles of Zinc chloride?
0.452mole ZnCl2×2mole HCl/1mole ZnCl2=0.904mole HCl

c)How many grams of Zn will react with 1.05 moles of HCl?
1.05mole HCl×1mole Zn/2mole HCl=0.525mole Zn  0.525mole Zn×65.4g/1mole=0.038mole H