Question

to test for the concentration of mercury (hg²+), a group of researchers poured an excess of ki (0.005 g) into a hair sample taken from a patient suffering from the disease. they found that it formed 0.001167 grams of the red precipitate hgi₂. now, we want to know how much mercury was in the sample. the first thing well notice is that from the balanced chemical equation we can see the ratio of hgi₂ to hg²+ is 1:1. this means that the moles of hgi₂ produced will be equivalent to the moles of hg²+ (or mercury in the hair sample). the problem is that we dont know how many moles of hgi₂ we have. we do know how many grams of hgi₂ we have, however. convert the gram value of hgi₂ into moles. how many moles is 0.001167 grams of hgi₂ equivalent to? the molar mass of hgi₂: 454.4 grams / 1 mole

Explanation:

Step1: Recall the formula for moles

The formula for calculating moles \(n\) is \(n=\frac{m}{M}\), where \(m\) is the mass and \(M\) is the molar mass.

Step2: Substitute the given values

We are given \(m = 0.001167\space g\) of \(HgI_{2}\) and \(M=454.4\space g/mol\) for \(HgI_{2}\).
Substituting into the formula \(n=\frac{0.001167\space g}{454.4\space g/mol}\)

Step3: Calculate the value

\(n=\frac{0.001167}{454.4}\space mol\approx 2.57\times 10^{-6}\space mol\)

Answer:

\(2.57\times 10^{-6}\)