IB chem Flashcards
What is stoichiometry?
The calculation of reactants and products in chemical reactions.
True or False: Stoichiometry is based on the conservation of mass.
True
Fill in the blank: In a balanced chemical equation, the number of _____ must be the same on both sides.
atoms
What does a mole represent in chemistry?
A mole represents 6.022 × 10²³ particles (atoms, molecules, etc.).
What is the purpose of balancing a chemical equation?
To ensure that the law of conservation of mass is followed.
Given the reaction 2H₂ + O₂ → 2H₂O, how many moles of water are produced from 4 moles of hydrogen?
4 moles of water.
What is the molar mass of water (H₂O)?
18.02 g/mol.
In the equation C₃H₈ + 5O₂ → 3CO₂ + 4H₂O, how many moles of oxygen are required to react with 1 mole of propane?
5 moles of oxygen.
True or False: Stoichiometric coefficients in a balanced equation can be fractions.
False
What is the stoichiometric ratio?
The ratio of the coefficients of reactants and products in a balanced equation.
How do you calculate the number of grams from moles?
Multiply the number of moles by the molar mass.
What is the limiting reactant?
The reactant that is completely consumed first in a chemical reaction.
If 2 moles of A react with 3 moles of B, what is the mole ratio of A to B?
2:3
Fill in the blank: Theoretical yield is the maximum amount of product that can be produced from a given amount of _____.
reactants
What is percent yield?
The ratio of actual yield to theoretical yield, expressed as a percentage.
True or False: In stoichiometry, only the mass of reactants is considered.
False
What is an excess reactant?
The reactant that remains after a chemical reaction has completed.
In the reaction 4Fe + 3O₂ → 2Fe₂O₃, how many moles of iron are required to produce 2 moles of iron(III) oxide?
4 moles of iron.
What is the first step in performing stoichiometric calculations?
Write and balance the chemical equation.
What does the term ‘yield’ refer to in stoichiometry?
The amount of product formed in a chemical reaction.
How do you determine the limiting reactant?
By comparing the mole ratios of the reactants used to the ratios in the balanced equation.
Fill in the blank: To convert from grams to moles, you divide the mass by the _____ of the substance.
molar mass
What role does stoichiometry play in chemical engineering?
It helps in scaling up reactions for industrial production.
What is the relationship between stoichiometry and chemical equilibrium?
Stoichiometry can be used to calculate concentrations of reactants and products at equilibrium.
True or False: Stoichiometry can only be applied to reactions in aqueous solutions.
False
What is the balanced equation for the combustion of methane (CH₄)?
CH₄ + 2O₂ → CO₂ + 2H₂O.
