8.5g of sample of iron required just 75cm3 of 3.00M HCl to dissolve it and give a neutral solution.Calculate the percentage purity of the sample of iron.

Fe + 2HCl ==> FeCl2 + H2

mols HCl = M x L = ?
mols Fe = 1/2 that (from the coefficients in the balanced equation)
g Fe = mols Fe x atomic mass Fe
%Fe or %purity = (g Fe/mass sample)*100 = ?
However, I don't buy your "throwaway statement" that FeCl2 solution is a neutral solution. I would bet money that it is acidic.

Percentage purity of sample iron 74.12%

Well, well, well. Looks like we have an iron conundrum on our hands. Let's break it down, shall we?

First, we need to determine the number of moles of HCl that reacted with the iron. To do that, we multiply the volume of HCl used (75 cm3) by its molarity (3.00 M) and divide it by 1000 to convert cm3 to dm3. This gives us:

(75 cm3 * 3.00 M) / 1000 = 0.225 moles of HCl

Now, it's time to figure out the number of moles of iron that reacted. According to the reaction equation, 1 mole of iron reacts with 6 moles of HCl. Since we used 0.225 moles of HCl, we divide it by 6 to get:

0.225 moles of HCl / 6 = 0.0375 moles of iron

Here comes the fun part. We know that 1 mole of iron corresponds to 55.85 grams. So, to calculate the mass of iron in our 8.5g sample, we multiply the number of moles of iron by its molar mass:

0.0375 moles of iron * 55.85 g/mol = 2.09 grams of iron

Now, we can finally determine the percentage purity of our sample of iron. To do that, we divide the mass of pure iron (2.09 grams) by the initial mass of the sample (8.5 grams) and multiply the result by 100:

(2.09 grams / 8.5 grams) * 100 = 24.59% purity

So, the percentage purity of the sample of iron is approximately 24.59%. I hope that brings a smile to your face!

To calculate the percentage purity of the sample of iron, we need to determine the number of moles of iron in the sample.

First, let's calculate the number of moles of HCl used in the reaction. We can use the molarity (3.00M) and the volume (75cm3) to do this.

Number of moles of HCl = Molarity × Volume
= 3.00M × 75cm3
= 225 millimoles (since 1 mole = 1000 millimoles)

Since the reaction between iron and HCl is 1:2 (one mole of iron reacts with two moles of HCl), we can infer that half the number of moles of HCl used will be the number of moles of iron present.

Therefore, number of moles of iron = 225 millimoles / 2
= 112.5 millimoles

Now let's calculate the mass of iron in the sample:

Mass of iron = number of moles × molar mass
= 112.5 millimoles × (atomic mass of Fe)
= 112.5 millimoles × 55.845 g/mol (atomic mass of iron based on the periodic table)

Lastly, let's calculate the percentage purity:

Percentage purity = (mass of pure iron / mass of sample) × 100
= (mass of iron / mass of sample) × 100

We do not have the mass of the sample given in the question, so we cannot directly calculate the percentage purity. To find the percentage purity, we need to know the mass of the sample.