Stoichiometry

Stoichiometry

2 slices bread + 1 slice ham 1 ham sandwich

What is stoichiometry?

Comes from the Greek words stoicheion, meaning element and metron, meaning measure.

In the real world, chemists perform reactions to make useful chemical compounds such as medicines, fibers, pigments, cosmetics and structural materials.

Because some reactants are expensive chemists don’t just mix huge quantities of chemicals together and hope for the best; rather they use stoichiometry to calculate the mass relationships between products and reactants.

Mole Ratios

Mole ratios are the key to stoichiometric calculations.

They give us the ratios between the amounts of reactants and products in any given reaction.

We get mole ratios from the coefficients.That’s why we need to start with a balanced

equation.

Mole Ratios

Start with a balanced equation

The coefficients represent moles

Divide one coefficient by the other to get the

mole ratio

Mole Ratios

2 slices bread 1 slice ham 1 ham sandwich

What is the mole ratio of bread slices to ham slices?

Mole Ratios


What is the mole ratio of bread slices to ham slices? 2/1

Mole Ratios



What is the mole ratio of ham slices to ham sandwiches?

Mole Ratios



What is the mole ratio of ham slices to ham sandwiches? 1/1

Mole Ratios




What is the mole ratio of ham sandwiches to bread slices?

Mole Ratios




What is the mole ratio of ham sandwiches to bread slices? 1/2

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen?

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide?

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3•What is the mole ratio of oxygen to water?

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3•What is the mole ratio of oxygen to water? 5/4

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3•What is the mole ratio of oxygen to water? 5/4•How many moles of carbon dioxide are made from 2 moles of propane?

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3•What is the mole ratio of oxygen to water? 5/4•How many moles of carbon dioxide are made from 2 moles of propane? 6

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3•What is the mole ratio of oxygen to water? 5/4•How many moles of carbon dioxide are made from 2 moles of propane? 6•Do you think you could determine how many kg of carbon dioxide are produced by one kg of propane? Take 2 minutes and write out your method.

Mole Ratios

C3H8 5O2 3CO2 4H2O

•What is the mole ratio of propane to oxygen? 1/5•What is the mole ratio of propane to carbon dioxide? 1/3•What is the mole ratio of oxygen to water? 5/4•How many moles of carbon dioxide are made from 2 moles of propane? 6•Do you think you could determine how many kg of carbon dioxide are produced by one kg of propane? Take 2 minutes and write out your method.

Convert 1 kg propane to moles > multiply by mole ratio of 3 to get moles of carbon dioxide > Convert moles of carbon dioxide to kg.

Stoichiometry

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