Final answer:
The number of moles in a sample of 9.0×10²¹ molecules of bromine gas (Br₂) is approximately 1.5 moles, using Avogadro's number for the calculation. None of the options provided in the question (5.6, 7.2, 9.6 moles) correspond to this calculation, indicating a possible typo in the question.
Step-by-step explanation:
To calculate the number of moles in a sample of 9.0×10²¹ molecules of bromine gas (Br₂), we need to use Avogadro's number, which is 6.022×10²³ molecules per mole. The number of moles (n) is calculated using the formula:
n = number of molecules / Avogadro's number
For 9.0×10²¹ molecules of Br₂:
n = (9.0×10²¹ molecules) / (6.022×10²³ molecules/mol)
n = 1.5×10²¸ moles
The closest answer to 1.5×10²¸ moles from the options given is 1.5 moles, which falls between option b (5.6 moles) and c (7.2 moles). However, both options are significantly higher than the calculated value. It seems there might be a typo in the options as none of them match the calculation. The correct number of moles for 9.0×10²¹ molecules of Br₂ is approximately 1.5 moles, which is not listed among the provided options.