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Questions and Answers
What is the role of the stoichiometric factor in the calculations for the reactions occurring simultaneously?
What is the role of the stoichiometric factor in the calculations for the reactions occurring simultaneously?
- To calculate the total volume of gas produced
- To convert grams of reactants to moles of products (correct)
- To balance the chemical equations
- To determine the limiting reactant
From the example calculations, how is the amount of H2 produced from Al calculated?
From the example calculations, how is the amount of H2 produced from Al calculated?
- By summing the weights of Al and Mg
- By multiplying the mass of Al by its molar mass
- By directly using the mass percentage of H2 in the alloy
- By applying the mole ratio from the balanced equation (correct)
In the given reactions, what is the balanced equation for the production of H2 from magnesium?
In the given reactions, what is the balanced equation for the production of H2 from magnesium?
- Mg(s) + HCl(aq) → MgCl2(aq) + 2 H2(g)
- Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) (correct)
- Mg(s) + 2 HCl(aq) → MgCl2(aq) + 2 H2(g)
- 2 Mg(s) + 2 HCl(aq) → 2 MgCl2(aq) + H2(g)
What mass of hydrogen gas is produced from 0.710 g of the magnesium-aluminum alloy sample?
What mass of hydrogen gas is produced from 0.710 g of the magnesium-aluminum alloy sample?
What is the molar mass of aluminum used in the stoichiometric calculations?
What is the molar mass of aluminum used in the stoichiometric calculations?
Which factor is used to convert from gas volume to moles in gas stoichiometry?
Which factor is used to convert from gas volume to moles in gas stoichiometry?
When calculating the mass of H2 produced from the magnesium reaction, which molar mass is used?
When calculating the mass of H2 produced from the magnesium reaction, which molar mass is used?
What is the total percentage composition of aluminum in the alloy described?
What is the total percentage composition of aluminum in the alloy described?
What is the molar ratio of CO2 produced to C6H14O4 consumed in the combustion reaction?
What is the molar ratio of CO2 produced to C6H14O4 consumed in the combustion reaction?
In the conversion pathway approach, what is the first step when calculating the mass of CO2 formed from triethylene glycol?
In the conversion pathway approach, what is the first step when calculating the mass of CO2 formed from triethylene glycol?
What is the balanced chemical equation for the combustion of triethylene glycol?
What is the balanced chemical equation for the combustion of triethylene glycol?
When using stoichiometric calculations, what is the purpose of identifying the limiting reagent?
When using stoichiometric calculations, what is the purpose of identifying the limiting reagent?
What is the molecular weight of triethylene glycol, C6H14O4, used in the calculations?
What is the molecular weight of triethylene glycol, C6H14O4, used in the calculations?
If you start with 4.16 g of C6H14O4, which step must be performed first to find the mass of CO2 produced?
If you start with 4.16 g of C6H14O4, which step must be performed first to find the mass of CO2 produced?
What is the mass of CO2 produced when burning 2.72 mol of triethylene glycol?
What is the mass of CO2 produced when burning 2.72 mol of triethylene glycol?
How much O2 is consumed for the complete combustion of 6.86 g of C6H14O4?
How much O2 is consumed for the complete combustion of 6.86 g of C6H14O4?
What does the stoichiometric coefficient of a substance in a balanced chemical equation represent?
What does the stoichiometric coefficient of a substance in a balanced chemical equation represent?
What is the mole ratio of O2 to H2O in the reaction 2H2 + O2 ⟶ 2H2O?
What is the mole ratio of O2 to H2O in the reaction 2H2 + O2 ⟶ 2H2O?
When conducting stoichiometric calculations, why is it important to use a balanced chemical equation?
When conducting stoichiometric calculations, why is it important to use a balanced chemical equation?
In stoichiometry, what does the term 'conversion pathway' typically refer to?
In stoichiometry, what does the term 'conversion pathway' typically refer to?
What constant represents the number of particles in one mole of a substance?
What constant represents the number of particles in one mole of a substance?
How would you calculate the mass of H2O produced from 5 moles of H2 in the reaction 2H2 + O2 ⟶ 2H2O?
How would you calculate the mass of H2O produced from 5 moles of H2 in the reaction 2H2 + O2 ⟶ 2H2O?
Study Notes
Stoichiometry
- Stoichiometry measures the elements in a chemical reaction, relating the amounts of substances in a reaction
- Stoichiometric factor (or mole ratio): Relates the amounts of any two substances involved in a chemical reaction, on a mole basis
Stoichiometric Factor Example
- Every 2 moles of H2 consumed, produces 2 moles of H2O
- Every 1 mole of O2 consumed, produces 2 moles of H2O
- Every 1 mole of O2 consumed, consumes 2 moles of H2
Example: Relating the numbers of moles of reactant & product
- Combustion of 2.72 mol of triethylene glycol, C6H14O4, in excess O2 produces 16.3 mol CO2
- Balanced chemical equation: 2 C6H14O4 + 15 O2 → 12 CO2 + 14 H2O
- The mole ratio of C6H14O4 to CO2 is 2:12
- From this ratio, we can calculate the moles of CO2 produced
Example: Relating the mass of a reactant & product
- The combustion of 4.16 g of C6H14O4 in excess O2 produces 7.31 g CO2
- The calculation involves converting grams of C6H14O4 to moles of C6H14O4, then moles of C6H14O4 to moles of CO2, and finally moles of CO2 to grams of CO2
Example: Relating the masses of two reactants to each other
- The combustion of 6.86 g of C6H14O4 in excess O2 consumes 226 g of C
Example: Calculating the quantity of a substance produced by reactions occurring simultaneously
- A Mg-Al alloy with 70.0% Al and 30.0% Mg by mass produces 0.0734 g of H2 when reacted with excess HCl
- The reaction involves two simultaneous reactions: Al + HCl and Mg + HCl
- The total amount of H2 produced is the sum of the amounts produced by each reaction
- To calculate the amount of H2, you need to consider the mass of Al and Mg in the alloy, convert them to moles, use the mole ratios from the balanced equations, and finally convert the moles of H2 to grams
Gas Stoichiometry
- Volume is a factor in stoichiometry for gases
- Ideal gas law: PV = nRT
- The volume of 1 mole of an ideal gas at 0°C (273.15 K) and 1 atm is 22.4 L (molar volume)
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Description
Explore the principles of stoichiometry, including the calculations of reactants and products in chemical reactions. This quiz covers examples such as the combustion of triethylene glycol and its resulting carbon dioxide production. Test your understanding of stoichiometric factors and mole ratios.
