Q152CP - Chemistry: Molecular Nature Of Matter And Change

Question

Hemoglobin is 6.0% heme (C₃₄H₃₂FeN₄O₄) by mass. To remove the heme, hemoglobin is treated with acetic acid and NaCl to form hemin (C₃₄H₃₂N₄O₄FeCl). At a crime scene, a blood sample contains 0.65 g of hemoglobin. (a) How many grams of heme are in the sample? (b) How many moles of heme? (c) How many grams of Fe? (d) How many grams of hemin could be formed for a forensic chemist to measure?

Step-by-Step Solution

Answer

1. There are 0.039 g of heme in the sample
2. There are 6.3×10^-5 mol of heme
3. There are 3.5×10^-3 g Fe.
4. There are of 4.1×10^-2 g hemin could formed for a forensic chemist to measure.

Step 1: Calculating amount of heme in sample

The mass of heme can be denoted as,

$Masspfheme=0.06\times 0.65g=0.039gheme$

Step 2: Calculating the moles of heme

The moles of heme can be find as,

$$\begin{gathered} \mathrm{Moles} \mathrm{of} \mathrm{heme}=0.039\mathrm{gheme}\times \frac{1\mathrm{mol} \mathrm{heme}}{616.5\mathrm{g} \mathrm{heme}} \\ \mathrm{Moles} \mathrm{of} \mathrm{heme}=6.326\times {10}^{-5} \\ \mathrm{Moles} \mathrm{of} \mathrm{heme}=6.3\times {10}^{-5}\mathrm{molheme} \end{gathered}$$

Step 3: Calculating amount of Fe

The mass of iron can be find using,

$$\begin{gathered} MassofFe=6.326\times {10}^{-5}molheme\times \frac{1molFe}{1molheme}\times \frac{55.85gFe}{1molFe} \\ MassofFe=3.5\times {10}^{-3}gFe \end{gathered}$$

Step 4: Calculating amount of hemin could be formed for a forensic chemist to measure

The mass of hemin can be denoted as,

$$\begin{gathered} \mathrm{Mass} \mathrm{of} \mathrm{hemin}=6.326\times {10}^{-5}\mathrm{molheme}\times \frac{1\mathrm{mol} \mathrm{hemin}}{1\mathrm{mol} \mathrm{heme}}\times \frac{651.94\mathrm{g} \mathrm{hemin}}{1\mathrm{mol} \mathrm{hemin}} \\ \mathrm{Mass} \mathrm{ofhemin}=4.1\times {10}^{-2}\mathrm{g} \mathrm{hemin} \end{gathered}$$