Stoichiometry, Limiting Reactants, and Percent Yield

2H₂  +   O₂  →  2H₂O
How many moles of oxygen are consumed if 8 moles H₂ are used?

• 2
• 4
• 6
• 8

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NGSS.HS-PS1-7

2 KClO₃ → 2 KCl + 3 O₂

How many moles of oxygen are produced when 6.7 moles of KClO₃ react?

• 6.7 mol

• 1.0 mol

• 10.1 mol

• 4.5 mol

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NGSS.HS-PS1-7

2Na + 2H₂O → 2NaOH+ H₂

How many grams of hydrogen are produced if 120 g of Na are available? The molar mass of Na is 23 g. The molar mass of H2 is 2 g.

• 5.2 g

• 2.6 g

• 690 g

• 45 g

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NGSS.HS-PS1-7

What is stoichiometry?

• Whether a precipitate is formed in a chemical reaction

• Whether a reaction is endothermic or exothermic

• How quantities of reactants and quantities of products are related

• How many chemical changes each reaction goes through

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NGSS.HS-PS1-7

CH₄ + 2 O₂ → CO₂ + 2 H₂O

How many moles of carbon dioxide are produced from the combustion of 110 g of CH₄?

• 13.7 mol

• 2.75 mol

• 6.11 mol

• 6.88 mol

Which is true due to the Law of Conservation of Matter?

• Mass of reactants < mass of products

• Mass of reactants > mass of products

• Mass of reactants = mass of products

• Mass of reactants and mass of products are unrelated.

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NGSS.HS-PS1-7

4 Al + 3 O₂ –> 2 Al₂O₃ 

How many moles of aluminum would be needed to react with 45 grams of O₂?

• 1.05 moles
• 3.75 moles
• 2.06 moles

• 1.875 moles

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NGSS.HS-PS1-7

Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)

How many moles of Fe can be made from 135 L H₂? 

• 4.02 moles Fe

• 6.99 moles Fe

• 9.13 moles Fe

• 2.81 moles Fe

2Al + 3H₂SO₄ -> Al₂(SO₄)₃ + 3H₂

How many grams of Al would react with 2.55 mol H₂SO₄? The molar mass of Al is 27 g.

• 15.6 g

• 45.9 g

• 459 g

• 870 g

Use the equation 2 Al + 3 Cl₂ ---> 2 AlCl₃.  If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant.

• AlCl3
• Cl2
• Al

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NGSS.HS-PS1-7