How many molecules are in 2.00 moles of H2O?
The correct answer and explanation is :
To calculate how many molecules are in 2.00 moles of water (H₂O), we need to use Avogadro’s number, which is a constant that represents the number of particles (atoms, molecules, etc.) in one mole of a substance.
Step-by-step explanation:
- Avogadro’s Number:
Avogadro’s number is 6.022×10236.022 \times 10^{23} molecules per mole. This means that one mole of any substance contains 6.022×10236.022 \times 10^{23} individual particles (atoms, molecules, etc.). - Number of molecules in 1 mole of H₂O:
In 1 mole of water (H₂O), there are 6.022×10236.022 \times 10^{23} water molecules. This value is independent of the substance and applies to all compounds. - Calculate the number of molecules in 2.00 moles of H₂O:
Since 1 mole of H₂O contains 6.022×10236.022 \times 10^{23} molecules, the number of molecules in 2.00 moles of H₂O will be: 2.00 moles×(6.022×1023 molecules per mole)=1.2044×1024 molecules2.00 \, \text{moles} \times \left( 6.022 \times 10^{23} \, \text{molecules per mole} \right) = 1.2044 \times 10^{24} \, \text{molecules}
Final Answer:
There are 1.2044×10241.2044 \times 10^{24} molecules in 2.00 moles of H₂O.
Conceptual Understanding:
This calculation illustrates a fundamental concept in chemistry known as the mole. The mole is a convenient way to count large quantities of very small entities like atoms or molecules. By knowing the number of moles, Avogadro’s number provides a direct link to the actual number of molecules.
The significance of Avogadro’s number stems from its universality: regardless of the substance, whether it’s water, carbon dioxide, or any other molecule, 1 mole of the substance always contains exactly 6.022×10236.022 \times 10^{23} molecules. This consistency helps chemists relate macroscopic quantities (such as grams) to microscopic quantities (like individual molecules).