Definitions
What is stoichiometry?
The calculation of quantities in chemical reactions using balanced equations.
What is a limiting reactant?
The reactant used up first that limits product formed.
How many moles of O₂ are needed to react with 2 moles of H₂ in: 2H₂ + O₂ → 2H₂O?
1 mole O₂
What is the molar mass of CO₂?
44 g/mol
How many moles of NaCl are produced in: Na + Cl₂ → 2NaCl (balanced: 2Na + Cl₂ → 2NaCl) using 2 moles Na?
2 moles NaCl
What law is stoichiometry based on?
Law of Conservation of Mass.
What is excess reactant?
The reactant left over after the reaction ends.
How many moles of H₂O are produced from 4 moles H₂?
4 moles H₂O
Convert 36 g H₂O to moles.
2 moles
How many moles of Cl₂ are needed for 4 moles Na?
2 moles Cl₂
What is the first step in stoichiometry problems?
Write and balance the equation.
What does a coefficient represent?
Number of molecules or moles.
How many moles of CO₂ form from 2 moles CH₄ in: CH₄ + 2O₂ → CO₂ + 2H₂O?
2 moles CO₂
Convert 88 g CO₂ to moles.
2 moles
How many grams of O₂ are in 2 moles O₂?
64g
What conversion factor links grams and moles?
Molar mass.
Why must equations be balanced?
To follow conservation of mass.
How many moles of O₂ are needed for 3 moles CH₄?
6 moles O₂
How many grams of H₂O are produced from 2 moles H₂?
36 g
How many moles are in 32 g O₂?
1 mole
What conversion factor links moles and moles?
Mole ratio.
What are the 3 common stoichiometry conversions?
Grams to moles, moles to moles, moles to grams
What is the molar mass of H₂O?
18 g/mol
How many grams of CO₂ are produced from 1 mole CH₄?
44 g
How many molecules are in 1 mole?
6.022 × 10²³ molecules