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Ethylene can be produced by the pyrolysis of ethane: C₂H₆ ⟶ C₂H₄ + H₂. If 20 g of ethane is used, what is the maximum mass of ethylene produced?

a) 20 g
b) Greater than 20 g
c) Less than 20 g
d) Not enough information to determine

User Pringles
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1 Answer

5 votes

Final answer:

Using stoichiometry and the law of conservation of mass, the maximum mass of ethylene produced from 20 g of ethane is less than 20 g, considering the molar masses of ethane and ethylene.

Step-by-step explanation:

The question involves the pyrolysis of ethane to produce ethylene, which is an example of a chemical reaction. Using stoichiometry, we can solve for the maximum mass of ethylene produced from 20 g of ethane.

The balanced chemical equation is C₂H₆ ⟶ C₂H₄ + H₂. Considering that no atoms are lost or gained during a chemical reaction and the law of conservation of mass, the total mass of products will be equal to the total mass of reactants.

The molar mass of ethane (C₂H₆) is approximately 30 g/mol, and the molar mass of ethylene (C₂H₄) is about 28 g/mol. If starting with 20 g of ethane:

  • Convert the mass of ethane to moles: 20 g / 30 g/mol = 0.67 moles of C₂H₆.
  • Use the stoichiometry of the reaction to find moles of C₂H₄ produced, which will be the same (1:1 ratio).
  • Convert the moles of ethylene to mass: 0.67 moles * 28 g/mol = 18.76 g of C₂H₄.

Thus, the maximum mass of ethylene produced will be less than 20 g, so the correct answer is (c) Less than 20 g.

User Jskunkle
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8.2k points
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