Final answer:
To calculate the number of atoms in a compound, first find the number of moles using the mass and relative formula mass; then multiply the moles by Avogadro's number (6.022×1023 atoms/mole).
Step-by-step explanation:
When calculating the number of atoms in a compound, you use the equation moles = mass / RFM (Relative Formula Mass). This calculation enables you to find the number of moles in a given sample. Then, to get the number of atoms, you multiply the number of moles by Avogadro's number, which is 6.022×1023 atoms/mole. This process is a prime example of stoichiometric calculations often performed in chemistry to relate mass, mole, and number of particles in a substance.
For instance, if you have a mass of glucose (C6H12O6), you would first calculate its molar mass, then use the mass of your sample divided by this molar mass to obtain the moles of glucose. The final step is to multiply the moles of glucose by Avogadro's number to determine the number of molecules of glucose you have.
To summarize the steps:
- Calculate the Relative Formula Mass (RFM), which is the sum of the atomic masses of all atoms in the formula.
- Determine the number of moles using the equation moles = mass / RFM.
- Multiply the number of moles by Avogadro's number to find the number of atoms.