Molar Mass Calculations and Examples
This page provides a comprehensive guide on calculating molecular and molar masses, along with practical examples to illustrate key concepts in chemistry.
The document begins with an example of calculating the molecular mass of carbon dioxide CO2.
Example: For CO₂, the calculation is as follows:
mCO₂ = mC + 2 × mO = 12u + 2 × 16u = 44u
This example demonstrates how to use atomic masses to determine the molecular mass of a compound.
Next, the guide moves on to calculating the molar mass of nitric acid HNO3.
Example: For HNO₃, the calculation is:
MHNO₃ = MH + MN + 3 × MO = 1 + 14 + 3 × 16 = 63 g/mol
This example shows how to determine the molar mass of a compound by summing the molar masses of its constituent elements.
The final example on this page deals with calculating the number of moles of water H2O in a given mass of the compound.
Example: Given 45g of H₂O, the calculation uses the proportion method:
1 mol H₂O - 18g
n H₂O - 45g
n = 45 × 1 / 18 = 2.5 moles
This example illustrates how to determine the number of moles when given a specific mass of a compound.
Vocabulary:
- Molar mass: The mass of one mole of a substance, expressed in grams per mole g/mol.
- Molecular mass: The sum of the atomic masses of all atoms in a molecule, expressed in atomic mass units u.
Highlight: Understanding how to calculate molar and molecular masses is crucial for solving many chemistry problems, including stoichiometry and concentration calculations.
The page effectively covers key concepts such as obliczanie masy cząsteczkowej i molowej, masa molowa CO2, and jak obliczyć liczbę moli, providing a solid foundation for students learning about molar calculations in chemistry.
