A 0.02718 mg sample of an unknown compound was found to contain 0.0094 mg of Fe, and 0.0178 mg of Cl. It was also determined that the unknown compound had a molecular weight of 162.10 g/mol. What is the molecular formula for this compound?
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To determine the molecular formula of the compound, we first need to calculate the number of moles of each element present in the sample.
Step 1: Calculate the number of moles of Fe (iron):
To calculate the number of moles of Fe, we use the formula:
Number of moles = Mass of element / molar mass
Given that the mass of Fe is 0.0094 mg and the molar mass of Fe is 55.85 g/mol, we can calculate the number of moles of Fe:
Number of moles of Fe = 0.0094 mg / 55.85 g/mol = 1.681 × 10^(-7) mol
Step 2: Calculate the number of moles of Cl (chlorine):
Using the same formula, we can calculate the number of moles of Cl:
Number of moles of Cl = 0.0178 mg / 35.45 g/mol = 5.024 × 10^(-7) mol
Step 3: Calculate the number of moles of the unknown compound:
To find the number of moles of the unknown compound, we need to subtract the moles of Fe and Cl from the total moles in the sample.
Total moles in the sample = 0.02718 mg / 162.10 g/mol = 1.678 × 10^(-7) mol
Number of moles of the unknown compound = Total moles - (moles of Fe + moles of Cl)
= (1.678 × 10^(-7) mol) - (1.681 × 10^(-7) mol + 5.024 × 10^(-7) mol)
= - 4.027 × 10^(-7) mol
Step 4: Determine the empirical formula:
Since the calculated number of moles of the unknown compound is negative, it means that there was an error in the measurements or calculations. This implies that the data given in the question is not consistent.
Without consistent data, it is not possible to determine the molecular formula of the compound.