mole and molar mass

​Moles & Molar Mass

​Avogadro's Number - 6.02 x 10²³ atoms/mole

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​1 mole of any element or compound has 6.02x10²³ atoms or molecules

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​But each atom or molecule has a different mass

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​Molar Mass - the mass of a mole of an element is given by its atomic mass

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• ​The molar mass of carbon is 12.01 g/mole

• ​The molar mass of oxygen is 15.99 g/mole

• ​The molar mass of CO is 12.01 + 15.99 = 28.0 g/mole

​Mole Ratio's

​Mole Ratio's are a ratio between the numbers of molews of any two of the substances in a balanced chemical equation.

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​CH₄ + 2O₂ --> CO₂ + 2H₂O

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​The mole ratio between CH₄ / O₂ = 1/2

​The mole ratio between CH₄ / CO₂ = 1/1

​the mole ratio between CH₄ / H₂O = 1/2

​The mole ratio between O₂ / H₂O = 2/2.

Multiple Choice

What do we call the mass of one mole?

• Atomic Number

• Molality

• Molarity

• Molar Mass

Multiple Choice

What is the molar mass of Potassium?

• 19

• 39.098 g/mole

• +1

• 209 g/mole

Multiple Choice

2H₂ + O₂ --> 2H₂O

How many moles of O2 will be required to react with 6 moles of H2 ?

• 1 mole O₂

• 4 moles O₂

• 3 moles O₂

• 8 moles O₂

Multiple Choice

Using the balanced chemical equation:

Mg + 2 HCl --> MgCl₂ + H₂

How many grams of MgCl₂ is produced if 4.67 moles of HCl react?

• 219 g MgCl₂

• 4.67 g MgCl₂

• 94 g MgCl₂

Multiple Choice

Using the balanced chemical equation:

4NH₃ + 3O₂ --> 2N₂ + 6H₂O

Determine the amount of grams of N₂ is produced if 4.03 moles of NH₃ react?

• 28.0 g N₂

• 56.4 g N₂

• 2.02 g N₂

Multiple Choice

Using the balanced chemical equation:

2C₄H₁₀ + 13O₂ --> 10H₂O + 8CO₂

Calculate the number of grams of C₄H₁₀ needed to produce 5.12 moles of CO₂.

• 58.0 g C₄H₁₀

• 2.56 g C₄H₁₀

• 74.2 g C₄H₁₀

Multiple Choice

N₂ +  3H₂ → 2NH₃ 
How many moles of hydrogen are needed to react with 2 moles of nitrogen?

• 6
• 2
• 3
• 1

Multiple Choice

Given the reaction: 4Al + 3O₂ --> 2Al₂O₃

How many moles of Aluminum oxide, Al₂O₃, can you produce if you have 2 moles of Al?

• 3 mole

• 2 mole

• 1 mole

• 0.5 mole

Multiple Choice

What is the mole ratio of H₂O to H₃PO₄ in the following chemical equation?   P₄O₁₀ + 6 H₂O --> 4 H₃PO₄ 

• 6:4
• 4:6
• 1:3
• 3:1

Multiple Choice

What is the first thing you must do to solve a stoichiometry problem?

• Write a Balanced Equation

• Panic

• Find molar mass

Multiple Choice

Calculate the molar mass of propane

C₃H₈

• 13 g/mol

• 44 g/mol

• 99 g/mol