Final answer:
In 3.5 moles of sodium sulfide (Na₂S), there are 7 moles of sodium atoms because each molecule of sodium sulfide contains two sodium atoms.
Step-by-step explanation:
To calculate the number of moles of sodium atoms contained in 3.5 moles of sodium sulfide (Na₂S), we need to consider the chemical formula of the compound. Sodium sulfide is made up of two sodium atoms (Na) for every sulfide ion (S²⁻). Therefore, each mole of Na₂S will contain 2 moles of sodium atoms.
Using this stoichiometric relationship, the calculation for the number of moles of sodium atoms in 3.5 moles of sodium sulfide is as follows:
- Number of moles of Na in Na₂S = Number of moles of Na₂S * Number of Na atoms per molecule of Na₂S
- Number of moles of Na = 3.5 moles * 2 moles of Na/mole of Na₂S
- Number of moles of Na = 7 moles
- Therefore, there are 7 moles of sodium atoms in 3.5 moles of sodium sulfide.