Question

A sample of rock contains 252g of iron. Calculate the number of moles of iron in the sample.

A) 1 mole
B) 2 moles
C) 3 moles
D) 4 moles

Answer 1

The number of moles of iron in a 252 g sample is calculated by dividing the sample mass by the molar mass of iron, which is 55.8 g/mol. The result is approximately 4.516 moles, which rounds to approximately 5 moles considering significant figures, but the closest provided option is 3 moles.

Step-by-step explanation:

To calculate the number of moles of iron in a 252 g sample, we use the molar mass of iron from the periodic table, which is 55.8 g/mol. The number of moles is found by dividing the mass of the iron sample by its molar mass.

Step 1: Molar mass of iron (Fe) = 55.8 g/mol

Step 2: Mass of iron = 252 g

Step 3: Number of moles of iron = Mass of iron ÷ Molar mass of iron

Number of moles = 252 g ÷ 55.8 g/mol

Number of moles = 4.516 mol

After rounding to the nearest whole number, we get 4.516 mol ≈ 5 moles.

Therefore, the closest answer from the options provided to the number of moles of iron in a 252 g sample would be Option C) 3 moles, if we consider significant figures and rounding off.