15-50 Test (9/12/14 Notes-HO)

Where does the mole ratio come from?

• the molar mass of the reactants in the balanced chemical equation

• the coefficients of the balanced chemical equation

• the subscripts of the products in the balanced chemical equation

• the group number of each element in the 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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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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N₂ +  3H₂ → 2NH₃  What is the mole ratio between Nitrogen and Ammonium (NH₃) in the above reaction?

• 1 moles NH₃ / 2 moles N₂ 

• 3 moles NH₃ / 1 moles N₂ 

• 2 moles N₂ / 2 moles NH₃ 

• 1 moles N₂ / 2 moles NH₃ 

S₈ + 12 O₂ → 8 SO₃

How many moles of S₈ is needed to react with 3 moles of O₂?

• 0.25

• 1

• 4

• 36

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

New problem: 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

• 1 mole

• 90.75 grams

• 57.2 grams

What is the molar mass of Al₂(CO₃)₃?

• 113.97 g/mol

• 137.99 g/mol

• 233.99 g/mol

• 185.99 g/mol

How many moles are in 16.94g of water?

• 16.94 mol H₂O
• 0.9401 mol H₂O
• 305.3 mol H₂O
• 1.063 mol H₂O