Stoichiometry

A molar ratio comes from

• the coefficients of the balanced equation

• the molar mass of the product

• the periodic table

• Avagadro's number, 6.02 x 10²³

The molar ratio 

• acts as a conversion factor

• is not necessary if you have a periodic table

What unit would you put on the bottom for this conversion?

• mol O₂

• mol H₂S

• mol SO₂

1.  What is the ratio between sulphur dioxide and oxygen in in this equation?

• 1 mol SO₂ / 2 mol O₂

• 4 mol SO₂ / 6 mol O₂

• 2 mol SO₂ / 3 mol O₂

Look at your molar roadmap. You're starting at grams of oxygen and want to go to moles of oxygen. What is the first conversion factor you are going to use?

• molar mass

• molar ratio of H₂S to O₂

• Avogadro's number

Where did the 32.0 g O₂ come from?

• It was calculated by using the molar mass of oxygen on the periodic table and multiplying it by 2

• It was weighed on a digital scale

Look at your molar roadmap. What conversion factor will you use next?

• 

• 

Where did the numbers in this conversion factor come from?

• The coefficients in the balanced equation

• The subscripts in the balanced equation

• The molar mass

Look at your molar roadmap. What is your LAST conversion factor going to be?

• Molar mass of oxygen

• Molar mass of sulfur dioxide

• Molar ratio of sulfur dioxide and oxygen

• Avogadro's number

Complete the calculation, what is the final answer?

• 328 g SO₂​

• 36.5 g SO₂

• 1.34 g SO₂​