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Questions and Answers
What is the limiting reactant in a chemical reaction?
What is the limiting reactant in a chemical reaction?
- The reactant that runs out first. (correct)
- The reactant that is in excess.
- The product with the highest yield.
- The catalyst that speeds up the reaction.
What are the products of the reaction between zinc and hydrochloric acid?
What are the products of the reaction between zinc and hydrochloric acid?
- Hydrogen gas and zinc chloride (correct)
- Zinc oxide and water
- Water and zinc chloride
- Chlorine gas and zinc hydroxide
Which ratio is used to identify the limiting reactant?
Which ratio is used to identify the limiting reactant?
- Quantity of product per coefficient in the balanced equation.
- Quantity of reactant per product formed.
- Quantity of reactant per total number of atoms in the reaction.
- Quantity of reactant per coefficient in the balanced equation. (correct)
In the reaction Zn + 2HCl → H₂ + ZnCl₂, if you have 12 atoms of zinc and 8 molecules of HCl, which is the limiting reactant?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, if you have 12 atoms of zinc and 8 molecules of HCl, which is the limiting reactant?
If you have 3 moles of zinc and 4 moles of HCl, which is the limiting reactant?
If you have 3 moles of zinc and 4 moles of HCl, which is the limiting reactant?
What is the first step in determining the limiting reactant when given the mass of reactants?
What is the first step in determining the limiting reactant when given the mass of reactants?
What is the molar mass of zinc (Zn)?
What is the molar mass of zinc (Zn)?
What are the products of the reaction between ethane and oxygen gas?
What are the products of the reaction between ethane and oxygen gas?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, if you have 5 moles of ethane and 16 moles of oxygen gas, which is the limiting reactant?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, if you have 5 moles of ethane and 16 moles of oxygen gas, which is the limiting reactant?
What is the molar mass of oxygen gas (Oâ‚‚)?
What is the molar mass of oxygen gas (Oâ‚‚)?
How do you convert moles of a reactant to moles of a product?
How do you convert moles of a reactant to moles of a product?
What is the molar mass of ethane (C₂H₆)?
What is the molar mass of ethane (C₂H₆)?
What is the molar mass of water (Hâ‚‚O)?
What is the molar mass of water (Hâ‚‚O)?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, if you have 30 grams of ethane and 84 grams of oxygen gas, which reactant is the limiting reactant?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, if you have 30 grams of ethane and 84 grams of oxygen gas, which reactant is the limiting reactant?
What is the theorerical yield?
What is the theorerical yield?
What is the balanced chemical equation for the reaction between zinc and hydrochloric acid?
What is the balanced chemical equation for the reaction between zinc and hydrochloric acid?
How do you convert grams of a substance to moles?
How do you convert grams of a substance to moles?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, what is the coefficient for oxygen gas?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, what is the coefficient for oxygen gas?
Which of the following does the limiting reactant determine?
Which of the following does the limiting reactant determine?
What is the balanced chemical equation for the reaction between ethane and oxygen gas?
What is the balanced chemical equation for the reaction between ethane and oxygen gas?
How does the coefficient of a reactant in a balanced equation relate to determining the limiting reactant?
How does the coefficient of a reactant in a balanced equation relate to determining the limiting reactant?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, what is the coefficient of HCl?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, what is the coefficient of HCl?
What is the definition of molar mass?
What is the definition of molar mass?
Which of the following steps is crucial in solving stoichiometry problems involving limiting reactants?
Which of the following steps is crucial in solving stoichiometry problems involving limiting reactants?
What happens to the excess reactant in a chemical reaction?
What happens to the excess reactant in a chemical reaction?
Why is it important to identify the limiting reactant in a chemical reaction?
Why is it important to identify the limiting reactant in a chemical reaction?
In the balanced equation 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, how many moles of water are produced for every 2 moles of ethane consumed?
In the balanced equation 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, how many moles of water are produced for every 2 moles of ethane consumed?
Which unit is used to express molar mass?
Which unit is used to express molar mass?
What is the formula for calculating moles from grams?
What is the formula for calculating moles from grams?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, if you start with 65.39 grams of zinc and excess HCl, approximately how many moles of zinc chloride (ZnCl₂) can be produced?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, if you start with 65.39 grams of zinc and excess HCl, approximately how many moles of zinc chloride (ZnCl₂) can be produced?
In the balanced equation 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, how many moles of oxygen are required to react completely with 2 moles of ethane?
In the balanced equation 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, how many moles of oxygen are required to react completely with 2 moles of ethane?
What term describes a reactant that is not completely used up in a chemical reaction?
What term describes a reactant that is not completely used up in a chemical reaction?
In stoichiometry, what does the term 'coefficient' refer to?
In stoichiometry, what does the term 'coefficient' refer to?
For the reaction Zn + 2HCl → H₂ + ZnCl₂, if you have 2 moles of Zn, how many moles of HCl are needed for a complete reaction?
For the reaction Zn + 2HCl → H₂ + ZnCl₂, if you have 2 moles of Zn, how many moles of HCl are needed for a complete reaction?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, if you have 14 moles of O₂, how many moles of CO₂ can be produced?
In the reaction 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, if you have 14 moles of O₂, how many moles of CO₂ can be produced?
What is the first step in determining the limiting reactant if you are given grams of each reactant?
What is the first step in determining the limiting reactant if you are given grams of each reactant?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, what is the molar ratio of Zn to HCl?
In the reaction Zn + 2HCl → H₂ + ZnCl₂, what is the molar ratio of Zn to HCl?
Which of the following is true regarding the limiting reactant?
Which of the following is true regarding the limiting reactant?
How does the limiting reactant affect the amount of product formed?
How does the limiting reactant affect the amount of product formed?
Flashcards
Limiting Reactant
Limiting Reactant
The reactant that is completely consumed in a chemical reaction, determining the maximum amount of product formed.
Reaction of Zinc and HCl
Reaction of Zinc and HCl
Zinc reacts with hydrochloric acid to produce hydrogen gas and zinc chloride.
Identifying the Limiting Reactant
Identifying the Limiting Reactant
Divide the quantity of each reactant by its coefficient in the balanced equation; the smallest result indicates the limiting reactant.
Reaction of Ethane and Oxygen
Reaction of Ethane and Oxygen
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Theoretical Yield
Theoretical Yield
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Excess Reactant
Excess Reactant
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Limiting Reactant Calculation
Limiting Reactant Calculation
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Mole Ratio Comparison
Mole Ratio Comparison
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Gram to Gram Conversion
Gram to Gram Conversion
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Study Notes
Limiting Reactants Introduction
- The discussion focuses on identifying limiting reactants and solving stoichiometry problems involving them.
Reaction of Zinc and Hydrochloric Acid
- Zinc reacts with aqueous hydrochloric acid (HCl) to produce hydrogen gas (Hâ‚‚) and zinc chloride (ZnClâ‚‚).
- The balanced chemical reaction is: Zn + 2HCl → H₂ + ZnCl₂
Identifying the Limiting Reactant
- The limiting reactant is the one that runs out first in a reaction.
- To identify it, find the lowest quantity per coefficient ratio.
Situation A: 12 Atoms of Zinc and 8 Molecules of HCl
- Divide the quantity of each reactant by its coefficient in the balanced equation.
- For zinc: 12 atoms / 1 (coefficient of Zn) = 12
- For HCl: 8 molecules / 2 (coefficient of HCl) = 4
- HCl has the lowest quantity per coefficient ratio, making it the limiting reactant.
Situation B: 3 Moles of Zinc and 4 Moles of HCl
- Divide the number of moles of each reactant by its coefficient.
- For zinc: 3 moles / 1 = 3
- For HCl: 4 moles / 2 = 2
- HCl has the lower ratio (2 < 3), thus HCl is the limiting reactant.
- The ratio is 1:2, so 1 mol of zinc reacts with 2 mols of HCl
- 2 mols of Zinc will react with 4 mols of HCl
- We don't have 6 mols of HCl so we run out of HCl first
Situation C: 40 Grams of Zinc and 56 Grams of HCl
- Convert grams to moles by dividing by the molar mass.
- Molar mass of zinc (Zn) is 65.39 g/mol.
- Molar mass of HCl is approximately 36.458 g/mol.
- Moles of zinc = 40 g / 65.39 g/mol ≈ 0.6117 moles
- Moles of HCl = 56 g / 36.458 g/mol ≈ 1.536 moles
- Divide the moles by the coefficients:
- For zinc: 0.6117 moles / 1 = 0.6117
- For HCl: 1.536 moles / 2 = 0.768
- Zinc has the lower ratio, so zinc is the limiting reactant
Reaction of Ethane and Oxygen Gas
- Ethane (C₂H₆) reacts with oxygen gas (O₂) to produce carbon dioxide (CO₂) and water (H₂O).
- The balanced chemical equation is: 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
Part A: Limiting Reactant and Moles of CO2 Produced
- Given 5 moles of ethane and 16 moles of oxygen gas.
- Method 1: Find the limiting reactant by comparing the mole per coefficient ratio.
- For ethane: 5 moles / 2 = 2.5
- For O₂: 16 moles / 7 ≈ 2.29
- Oâ‚‚ has the lower ratio, so Oâ‚‚ is the limiting reactant.
- Method 2: Convert the moles of each reactant to moles of product (COâ‚‚), with reactant producing less product = limiting reacant
- Convert moles of ethane to moles of CO₂: 5 moles C₂H₆ * (4 moles CO₂ / 2 moles C₂H₆) = 10 moles CO₂
- Convert moles of O₂ to moles of CO₂: 16 moles O₂ * (4 moles CO₂ / 7 moles O₂) ≈ 9.14 moles CO₂
- Oâ‚‚ produces less COâ‚‚, therefore theorerical yield of CO2 is 9.14 moles
- The reactant that produces less product = limiting reactant
- The reactant that produce smaller theorerical yield is the limiting reactant
- The theoretical yield amount (9.14 moles) indicates that Oâ‚‚ is the limiting reactant.
Part B: Grams of Water Produced
- Given 30 grams of ethane and 84 grams of oxygen gas.
- Perform Gram to Gram conversion
- Convert 30g of ethane into grams of water
- Convert 84g of oxygen to grams of water
- Whichever is lest, this is the correct value and limiting reactant
Gram to Gram Conversions
- Molar mass of ethane (C₂H₆) = (2 * 12.01) + (6 * 1.008) ≈ 30.068 g/mol
- Molar Mass of water is 18.016 g/mol
- Conversion from ethane to water: 30 g C₂H₆ * (1 mol C₂H₆ / 30.068 g C₂H₆) * (6 mol H₂O / 2 mol C₂H₆) * (18.016 g H₂O / 1 mol H₂O) ≈ 53.93 g H₂O
- Molar mass of oxygen (Oâ‚‚) = 32 g/mol
- Conversion from oxygen to water: 84 g O₂ * (1 mol O₂ / 32 g O₂) * (6 mol H₂O / 7 mol O₂) * (18.016 g H₂O / 1 mol H₂O) ≈ 40.54 g H₂O
- The amount of water produced is the smaller of the two (40.54 g).
- Oxygen is the limiting reactant.
- Ethane is the excess reactant because it results in higher amount, thus not limitting.
Key Concepts
- Theoretical Yield: The maximum amount of product that can be formed in a reaction.
- The limiting reactant determines the theorerical yield.
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