Introduction to Stoichiometry

Where are the numbers for a mole ratio found?

• They are part of the chemical formulas for the reactants / products.

• They are given in the problem.

• They are found on the periodic table for those elements.

• They are found as coefficients in the reaction's balanced chemical equation.

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

Ethane (C₂H₆) combusts in the above reaction. What is the mole ratio of ethane to oxygen gas?

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Tags

NGSS.HS-PS1-7

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

Ethane (C₂H₆) combusts in the above reaction. What is the mole ratio of carbon dioxide to water?

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Tags

NGSS.MS-PS1-5

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

A problem asks how many moles of oxygen gas are needed to react completely with 6 moles of ethane (C₂H₆). What is the first step in setting up the problem?

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If 16 moles of carbon dioxide are formed by this reaction, how many moles of water were also produced?

• 4 mol H₂O

• 6 mol H₂O

• 24 mol H₂O

• 96 mol H₂O

• 384 mol H₂O

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

New problem: If 3.5 moles of oxygen gas are used up as ethane combusts completely, how many moles of carbon dioxide are produced?

• 0.5 mol CO₂

• 0.57 mol CO₂

• 2.0 mol CO₂

• 3.0 mol CO₂

• 3.5 mol CO₂

Tags

NGSS.HS-PS1-7

How many moles of ethane (C₂H₆) are required to produce 13.5 moles of water from the above reaction?

• 4.5 mol C₂H₆

• 27 mol C₂H₆

• 40.5 mol C₂H₆

• 81 mol C₂H₆

• 162 mol C₂H₆

Tags

NGSS.HS-PS1-7

Which mole ratio tells how much aluminum oxide is produced from 3 moles of aluminum?

• 3 mol Al/ 2 mol Al₂O₃

• 2 mol Al₂O₃/ 4 mol Al

• 4 mol Al/ 2 mol Al₂O₃

• 2 mol Al₂O₃/ 3 mol Al

What are the missing coefficients for the unbalanced equation below? Cr(s) + Fe(NO3)2(aq) → Fe(s) + Cr(NO3)3(aq)

• 2,3,3,2

• 1,3,3,1

• 2,3,2,3

• 2,3,1,2

What is the mole ratio of Ba(OH)₂ to AlPO₄?

• 3 mol Ba(OH)₂ / 2 mol AlPO₄

• 1 mol Ba(OH)₂/ 1 mol AlPO₄

• 2 mol Ba(OH)₂/ 3 mol AlPO₄

• 1 mol Ba(OH)₂/ 3 mol AlPO₄

Tags

NGSS.HS-PS1-7