A 37.2 g of iron ore is treated as follows. The
iron in the sample is all converted by a series
of chemical reactions to Fe2O3. The mass of
Fe2O3 is measured to be 11.1 grams. What
was the percent iron in the sample of ore?
Answer in units of percent
To find the percent of iron in the sample of ore, we need to calculate the mass percent.
First, let's find the mass of iron in the sample by subtracting the mass of Fe2O3 from the initial mass of the ore:
Mass of iron = Mass of ore - Mass of Fe2O3
Mass of iron = 37.2 g - 11.1 g
Mass of iron = 26.1 g
Next, we'll calculate the percent of iron in the sample using the formula:
Percent iron = (Mass of iron / Mass of ore) * 100
Percent iron = (26.1 g / 37.2 g) * 100
Percent iron = 70.16%
Therefore, the percent of iron in the sample of ore is 70.16%.
To find the percent iron in the sample of ore, we need to calculate the mass percent of iron in the Fe2O3 compound.
Step 1: Determine the molar masses of Fe and Fe2O3:
The molar mass of Fe (iron) is approximately 55.845 g/mol.
The molar mass of Fe2O3 (iron(III) oxide) can be calculated as follows:
(2 × molar mass of Fe) + (3 × molar mass of oxygen)
= (2 × 55.845 g/mol) + (3 × 16.00 g/mol)
= 111.69 g/mol + 48.00 g/mol
= 159.69 g/mol
Step 2: Calculate the number of moles of Fe2O3:
Number of moles = mass of Fe2O3 / molar mass of Fe2O3
Number of moles = 11.1 g / 159.69 g/mol
Step 3: Determine the number of moles of iron (Fe) in Fe2O3:
Since the molar ratio between Fe and Fe2O3 is 1:1, the number of moles of Fe is the same as the number of moles of Fe2O3.
Step 4: Calculate the mass of iron (Fe):
Mass of Fe = number of moles of Fe × molar mass of Fe
Mass of Fe = number of moles of Fe2O3 × molar mass of Fe
Step 5: Calculate the percent iron in the sample of ore:
Percent iron = (mass of Fe / mass of ore sample) × 100
Let's now substitute the values into the formula:
Percent iron = (11.1 g / 159.69 g) × 100
Calculating this expression provides the answer.