8.5g of sample of iron required 75cmcubic of 3mol of hcl to dissolve it and give neutral solution.calculate the percentage of purity of sample iron?
I think you have omitted the NaOH concentration and volume to acquire a neutral solution. Without that we have no way of knowing how much HCl was in excess after the iron was dissolved.
To calculate the percentage of purity of the sample of iron, you need to determine the amount of iron present in the sample and compare it to the total sample mass.
First, we need to calculate the number of moles of HCl used in the reaction. Given that the volume of 3 M HCl used is 75 cm³, and the molarity (M) represents the number of moles of solute per liter of solution, we can use the following equation:
Moles of HCl = Molarity × Volume (in liters)
Converting the volume from cm³ to liters:
Volume = 75 cm³ ÷ 1000 cm³/L = 0.075 L
Now, calculating the moles of HCl:
Moles of HCl = 3 mol/L × 0.075 L = 0.225 mol
Since the reaction between iron (Fe) and HCl follows a 1:1 stoichiometry, we can assume that the moles of HCl used is equal to the moles of iron present:
Moles of Fe = 0.225 mol
Next, let's calculate the molar mass of iron (Fe) using the periodic table:
Atomic mass of Fe = 55.845 g/mol
Now, we can calculate the mass of the sample of iron:
Mass of Fe = Moles of Fe × Molar mass of Fe
= 0.225 mol × 55.845 g/mol
= 12.56 g
Finally, we can calculate the percentage of purity of the sample of iron:
Percentage of purity = (Mass of pure iron / Total mass of sample) × 100
= (12.56 g / 8.5 g) × 100
= 147.76%
Therefore, the percentage of purity of the sample of iron is approximately 147.76%.
To calculate the percentage of purity of the iron sample, you need to determine the number of moles of iron in the sample and compare it to the moles of iron actually dissolved. Here are the steps to follow:
1. Calculate the number of moles of HCl used:
Given that 75 cm³ of a 3 M (3 mol/dm³) HCl solution was used, you can use the formula for moles:
Moles = Concentration (M) × Volume (dm³)
Moles of HCl = 3 mol/dm³ × 0.075 dm³ = 0.225 mol
2. Determine the stoichiometry of the reaction:
From the balanced equation between iron and HCl, you can see that the ratio of moles of HCl to moles of iron is 6:2 (from the equation: Fe + 2HCl -> FeCl₂ + H₂). This means that 2 moles of HCl react with 1 mole of iron.
3. Calculate the moles of iron:
Given that 0.225 moles of HCl react, you can set up a ratio:
0.225 mol HCl : 1 mol Fe = 2 mol HCl : x mol Fe
Cross-multiplying:
x = (0.225 mol Fe × 1 mol Fe) / 2 mol HCl
x = 0.1125 mol Fe
4. Convert the moles of iron to grams:
Since the molar mass of iron is 55.845 g/mol, you can calculate the mass of the iron:
Mass = Moles × Molar mass
Mass of Fe = 0.1125 mol × 55.845 g/mol
Mass of Fe = 6.26 g
5. Calculate the percentage of purity:
Finally, you can determine the percentage of purity by comparing the mass of pure iron to the mass of the original sample:
Percentage of purity = (Mass of pure iron / Mass of sample iron) × 100
Percentage of purity = (6.26 g / 8.5 g) × 100
Percentage of purity = 73.65%
Therefore, the percentage of purity of the sample iron is approximately 73.65%.