Mass-to-Mole Stoichiometry

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​Today, we will use ratios to build a
2-step conversions.

​“FAME IS A VAPOR, POPULARITY IS AN ACCIDENT, RICHES TAKE WINGS, THOSE WHO CHEER TODAY MAY CURSE TOMORROW AND ONLY ONE THING ENDURES – CHARACTER.

HARRY S. TRUMAN

Solving Complex Stoichiometry

2- Step Mole to Gram Conversions

Combining conversion ratios to solve more complex problems
1. Use mole to mole ratios
2. Use molar mass ratios

Solving Complex Stoichiometry

Steps

1. Ratios

   1. molar mass :

   2. mole to mole:

2. Given:

3. Want:

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Solving Complex Stoichiometry

 For the reaction Cl₂ + 2KBr → 2KCl + Br₂, how many grams of potassium chloride are produced from 4.3 moles of potassium bromide?

Hint: Underline/Highlight and or circle important Information.

​

Solving Complex Stoichiometry

For the reaction Cl₂ + 2KBr → 2KCl + Br₂, how many grams of potassium chloride are produced from 4.3 moles of potassium bromide?

molar mass ratio:

K 39.10
Cl 35.45 +

Multiple Choice

What is the correct molar mass of KCl?

• 74.55 g/mol

• 119.00 g/mol

• 39.10 g/mol

• 79.90 g/mol

​

Solving Complex Stoichiometry

For the reaction Cl₂ + 2KBr → 2KCl + Br₂, how many grams of potassium chloride are produced from 4.3 moles of potassium bromide?

mole to mole ratio:


_____KBr -> ____KCL

Multiple Choice

For the reaction Cl₂ + 2KBr → 2KCl + Br₂, how many grams of potassium chloride are produced from 4.3 moles of potassium bromide?

What is the mole-to-mole ratio of KCl and KBr?

• 1:1

• 1:2

• 2:2

• 2:1

​

Solving Complex Stoichiometry

Set up Extended T chart

Given

want

​Ratios

​For the reaction Cl₂ + 2KBr → 2KCl + Br₂, how many grams of potassium chloride are produced from 4.3 moles of potassium bromide?

​moles are in the heart

​

Solving Complex Stoichiometry

For the reaction Cl₂ + 2KBr → 2KCl + Br₂, how many grams of potassium chloride are produced from 4.3 moles of potassium bromide?

4.3 mol KBr

g KCl

​2 mol KCl

​2 mol KBr

mole to mole ratio

molar mass ratio

​ 1 mol KCl

​Moles are in the heart.

​74.55

Multiple Choice

 For the reaction 2Zn + O₂ → 2ZnO, how many grams of zinc oxide can be produced from 7.3 moles of oxygen? 

Calculate the molar mass ratio of O₂

• 16.00 g/mol

• 32.00 g/mol

• 81.38 g/mol

• 65.38 g/mol

Multiple Choice

 For the reaction 2Zn + O₂ → 2ZnO, how many grams of zinc oxide can be produced from 7.3 moles of oxygen? 

Calculate the molar mass ratio of ZnO

• 16.00 g/mol

• 32.00 g/mol

• 81.38 g/mol

• 65.38 g/mol

Multiple Choice

 For the reaction 2Zn + O₂ → 2ZnO, how many grams of zinc oxide can be produced from 7.3 moles of oxygen? 

What is the mole-to-mole ratio of O₂ to ZnO?

• 2:1

• 2:2

• 1:1

• 1:2

Labelling

 For the reaction 2Zn + O₂ → 2ZnO, how many grams of zinc oxide can be produced from 7.3 moles of oxygen? 

Set up the conversion.

Drag labels to their correct position on the image

1 mol O₂

32.00 g O₂

81.38 g ZnO

2 mol ZnO

1 mol ZnO

7.3 g O₂

Multiple Choice

 For the reaction 2Zn + O₂ → 2ZnO, how many grams of zinc oxide can be produced from 7.3 moles of oxygen?

• 1188.15 g ZnO

• 297.04 g ZnO

• 0.18 g ZnO

• 467.20 g ZnO