STEPS
What is the first step you take when doing stoichiometry?
Write the balanced equation.
What do you need to find when you convert moles to moles?
The Mole Ratio.
What is Stoichiometry?
Mass relationships between substances in a chemical reaction.
How do we convert grams to moles?
Divide by the molar mass
Fe3O4 + 4 CO--->3 Fe + 4 CO2
How many moles of CO are needed to react with
16.5 g of Fe3O4?
0.285 moles CO
What is the second step you take in stoichiometry?
Write down your 'known' & convert to moles if necessary
What do you need to find when you convert moles to grams?
Molar Mass.
What do we look at to find mole ratios?
The coefficients in a balanced equation.
What is Avogadro's number?
6.022x10^24
How many moles of Fe2O3 will form from 5.0 moles of Fe?
2.5 moles
What is the third step you take in stoichiometry?
Use conversion factors to convert to the substance you need
Given: 2H2+O2→2H2O
If you start with 6 moles of H2, how many moles of H2Ocan be produced (assuming excess of O2)?
6
What is Actual Yield?
Actual amount of a product that can be formed with the limiting reactant.
How do we convert moles to grams?
Multiply by molar mass.
How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas?
6 moles KClO3
What is the last step in stoichiometry?
Convert to grams if necessary or stop
Consider the balanced chemical equation:
N2 + 3H2 --> 2NH3
Question:
If 8 moles of H2 react with excess N2, how many moles of NH3 can be produced?
5.3
What is a Theoretical Yield?
The maximum amount of a product that can be given off.
What are you calculating for if you divide by 6.022x10^23 then multiply by molar mass?
Converting from particles to grams
How many grams of NaCl will be produced from 1.25 mol of chlorine gas reacting with sodium?
146 g
What is something you use to help you with the stoichiometry process?
Mole ratios
Fe+O2--->Fe2O3
Find the mole ratio of Iron to Oxygen
4:3
What is Excess Reactant?
Reactant that is not used up when a reaction is run to completion.
Al + O2 → Al2O3
What is the ratio of aluminum to oxygen?
4 to 3
Ammonium nitrate decomposes into dinitrogen monoxide gas and water. Determine the amount in grams of water produced if 25.0 g of ammonium nitrate decomposes.
11.3grams H2O