Flashcard library · Chemistry
Chemistry: Stoichiometry Basics
This flashcard deck provides a foundational understanding of stoichiometry, an essential topic in chemistry. It covers core concepts from mole conversions and balancing equations to limiting reactants and percent yield. Master these fundamental principles to confidently tackle quantitative problems in chemical reactions.
Want to actually learn these?
Create a free NoteFren account to study with spaced repetition, or turn your own notes into cards like these.
What is stoichiometry?
Stoichiometry is the branch of chemistry that deals with the quantitative relationships between reactants and products in chemical reactions. It is based on the Law of Conservation of Mass.
State the Law of Conservation of Mass in the context of chemical reactions.
The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. Therefore, the total mass of reactants must equal the total mass of products.
What is a mole (mol) in chemistry?
A mole is the SI unit for the amount of substance, defined as the amount of substance that contains as many elementary entities (atoms, molecules, ions) as there are atoms in exactly 12 grams of carbon-12.
What is Avogadro's number and what does it represent?
Avogadro's number is approximately 6.022 x 10^23. It represents the number of particles (atoms, molecules, ions, etc.) in one mole of any substance.
How is molar mass defined and what are its common units?
Molar mass is the mass of one mole of a substance. Its common units are grams per mole (g/mol).
Why is it essential to balance a chemical equation before performing stoichiometric calculations?
Balancing a chemical equation ensures that the Law of Conservation of Mass is upheld. It provides the correct mole ratios between reactants and products, which are crucial for accurate stoichiometric calculations.
What do the coefficients in a balanced chemical equation represent in terms of stoichiometry?
The coefficients in a balanced chemical equation represent the relative number of moles (or molecules/formula units) of each reactant and product involved in the reaction.
If you have 2 moles of O2, how many molecules of O2 are present?
You would have 2 multiplied by Avogadro's number (2 x 6.022 x 10^23 molecules), which is 1.2044 x 10^24 molecules of O2.
How do you convert grams of a substance to moles?
To convert grams to moles, you divide the given mass in grams by the molar mass of the substance (moles = mass / molar mass).
Describe the general steps for a mass-to-mass stoichiometric calculation.
First, convert the given mass of the known substance to moles. Second, use the mole ratio from the balanced equation to convert moles of the known substance to moles of the desired substance. Third, convert moles of the desired substance to its mass.
What is a limiting reactant (or limiting reagent)?
The limiting reactant is the reactant that is completely consumed first in a chemical reaction, thereby determining the maximum amount of product that can be formed.
How do you identify the limiting reactant in a chemical reaction?
To identify the limiting reactant, calculate the amount of product that can be formed from each reactant individually, assuming the others are in excess. The reactant that produces the least amount of product is the limiting reactant.
What is theoretical yield?
Theoretical yield is the maximum amount of product that can be formed from a given amount of reactants, calculated based on the stoichiometry of the balanced chemical equation.
What is actual yield?
Actual yield is the amount of product actually obtained from a chemical reaction performed in a laboratory setting. It is usually less than the theoretical yield due to various factors.
How is percent yield calculated and what does it indicate?
Percent yield is calculated as (actual yield / theoretical yield) x 100%. It indicates the efficiency of a chemical reaction in producing the desired product.