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What is the purpose of a mole ratio in a chemical reaction?
What is the purpose of a mole ratio in a chemical reaction?
What type of equation shows the reactants and products as molecules?
What type of equation shows the reactants and products as molecules?
What is the formula to calculate the amount of product formed in a reaction?
What is the formula to calculate the amount of product formed in a reaction?
What is the limiting reagent in a reaction?
What is the limiting reagent in a reaction?
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What is the formula to calculate the percent yield of a reaction?
What is the formula to calculate the percent yield of a reaction?
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What unit is used to express the amount of product formed in a reaction?
What unit is used to express the amount of product formed in a reaction?
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How is the amount of reactant required calculated in a reaction?
How is the amount of reactant required calculated in a reaction?
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What is the purpose of a mole ratio in stoichiometric calculations?
What is the purpose of a mole ratio in stoichiometric calculations?
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In a mole-to-mole calculation, the conversion factor is always the molar mass of a substance.
In a mole-to-mole calculation, the conversion factor is always the molar mass of a substance.
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The balanced chemical equation is not necessary for stoichiometric calculations.
The balanced chemical equation is not necessary for stoichiometric calculations.
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Mass-to-mass calculations relate the number of moles of one substance to the mass of another substance.
Mass-to-mass calculations relate the number of moles of one substance to the mass of another substance.
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The units of the answer must be checked at the end of a stoichiometric calculation.
The units of the answer must be checked at the end of a stoichiometric calculation.
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Stoichiometric calculations can only be used for reactions with a 1:1 mole ratio.
Stoichiometric calculations can only be used for reactions with a 1:1 mole ratio.
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Mole-to-mass calculations involve the use of the molar mass of a substance.
Mole-to-mass calculations involve the use of the molar mass of a substance.
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The mole ratio is always a whole number in a balanced chemical equation.
The mole ratio is always a whole number in a balanced chemical equation.
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The first step in a stoichiometric calculation is to identify the known and unknown quantities.
The first step in a stoichiometric calculation is to identify the known and unknown quantities.
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Study Notes
Mole Ratios
- A mole ratio is a ratio of the amount of one substance to the amount of another substance in a reaction.
- It is used to relate the amount of reactants and products in a chemical reaction.
- Mole ratios are derived from the coefficients of a balanced chemical equation.
- The mole ratio of reactants to products can be used to determine the amount of product formed or the amount of reactant required.
Molecular Equations
- A molecular equation is a chemical equation that shows the reactants and products as molecules.
- It does not show the ionic species present in the reaction.
- Molecular equations are not balanced in terms of ions, but rather in terms of molecules.
- Molecular equations are often used to represent reactions that occur in non-aqueous solutions or in the gas phase.
Stoichiometric Calculations
Amount of Product Formed
- The amount of product formed can be calculated using the mole ratio and the amount of reactant.
- The formula is: amount of product = mole ratio x amount of reactant
- Units: moles, grams, or volume (for gases)
Amount of Reactant Required
- The amount of reactant required can be calculated using the mole ratio and the amount of product.
- The formula is: amount of reactant = mole ratio x amount of product
- Units: moles, grams, or volume (for gases)
Limiting Reagent
- The limiting reagent is the reactant that is consumed completely in a reaction.
- It determines the amount of product formed.
- The limiting reagent can be identified by calculating the amount of product formed from each reactant and determining which reactant produces the least amount of product.
Percent Yield
- The percent yield is the ratio of the actual amount of product formed to the theoretical amount of product.
- The formula is: percent yield = (actual amount of product / theoretical amount of product) x 100
- Units: percentage
Mole Ratios
- A ratio of the amount of one substance to the amount of another substance in a reaction, used to relate reactants and products.
- Derived from coefficients of a balanced chemical equation.
- Used to determine amount of product formed or amount of reactant required.
Molecular Equations
- A chemical equation showing reactants and products as molecules.
- Does not show ionic species present in the reaction.
- Balanced in terms of molecules, not ions.
- Often used to represent reactions in non-aqueous solutions or gas phase.
Stoichiometric Calculations
Amount of Product Formed
- Calculated using mole ratio and amount of reactant: amount of product = mole ratio x amount of reactant.
- Units: moles, grams, or volume (for gases).
Amount of Reactant Required
- Calculated using mole ratio and amount of product: amount of reactant = mole ratio x amount of product.
- Units: moles, grams, or volume (for gases).
Limiting Reagent
- The reactant consumed completely in a reaction, determining amount of product formed.
- Identified by calculating amount of product formed from each reactant and finding the reactant producing the least amount of product.
Percent Yield
- The ratio of actual amount of product formed to theoretical amount of product: percent yield = (actual amount of product / theoretical amount of product) x 100.
- Units: percentage.
Stoichiometric Calculations
- Involve the use of balanced chemical equations to determine the amount of reactants required or products formed in a chemical reaction.
Types of Stoichiometric Calculations
- Mole-to-Mole Calculations: relate the number of moles of one substance to the number of moles of another substance.
- Mole-to-Mass Calculations: relate the number of moles of a substance to its mass.
- Mass-to-Mass Calculations: relate the mass of one substance to the mass of another substance.
Steps for Stoichiometric Calculations
- Write and Balance the Equation: ensure that the number of atoms of each element is equal on both the reactant and product sides.
- Identify the Known and Unknown Quantities: identify the known quantities (e.g. amount of reactant) and the unknown quantities (e.g. amount of product).
- Choose a Conversion Factor: choose a conversion factor (e.g. mole ratio, molar mass) to relate the known and unknown quantities.
- Perform the Calculation: use the chosen conversion factor to perform the calculation.
- Check the Units: ensure that the units of the answer are correct.
Stoichiometric Calculation Examples
Mole-to-Mole Calculation
- Calculate the number of moles of oxygen required to react with 2 moles of hydrogen to form water.
- Use the conversion factor: 2H2 + O2 → 2H2O (2:1 mole ratio).
- Calculate: 2 moles H2 × (1 mole O2 / 2 moles H2) = 1 mole O2.
Mole-to-Mass Calculation
- Calculate the mass of carbon dioxide produced when 1 mole of calcium carbonate is heated.
- Use the conversion factor: CaCO3 → CaO + CO2 (1:1 mole ratio, molar mass of CO2 = 44 g/mol).
- Calculate: 1 mole CaCO3 × (1 mole CO2 / 1 mole CaCO3) × 44 g/mol = 44 g CO2.
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Description
Learn about mole ratios, relating reactants and products in chemical reactions, and molecular equations in chemistry.
