Post on 17-Dec-2015
Symbolic notation used by chemists to represent a
chemical reaction.
Chemical Equation
In a chemical equation, everything to the left of the
arrow
Reactant – starting materials
In a chemical equation, everything to the right of
the arrow
Product – ending materials
Coefficient
Number in front of a formula. Tells how many formula units are present.
Balanced chemical equation
Demonstrates conservation of mass.
Same # of each element on both sides.
Chemical equations demonstrate conservation
of
mass, charge (& energy)
Reaction with 1 product
Synthesis
Reaction with 1 reactant
Decomposition
Reaction of 1 element with 1 compound to produce a
new element & a new compound
Single Replacement
Reaction of 2 compounds to produce 2 new
compounds.
Double Replacement
Reaction with oxygen. One of the reactants must be
O2.
Combustion
AB A + B
Decomposition
A + B AB
Synthesis
AX + B A + BX
Single Replacement
AX + BY AY + BX
Double Replacement
To predict if a single replacement reaction will
occur,
You must compare the reactivity of the free element with the corresponding element in the compound. Use Table J. If the stand-alone element is above the corresponding element in the compound, the reaction will take place.
Na + MgCl2 ?
Compare Na & Mg (both metals). Na is above Mg in Table J so the rxn occurs.
2Na + MgCl2 2NaCl + Mg
Do the following reactions occur?
• Br2 + HF: Compare Br2 & F2
• Mg + ZnCl2: Compare Mg & Zn
• Na + HCl: Compare Na & H2
• Ag + LiBr: Compare Ag & Li
No
Yes
Yes
No
Stoichiometry Problems
Use the relationship in the balanced equation to predict amounts consumed or produced.Use the equation to set up a ratio.
2Na + 2H2O 2NaOH + H2
How many moles of hydrogen are produced when 4 moles of
sodium reacts completely?
2 Moles of hydrogen!X4
4/2 = X/1 so X = 2