Question

1. calculate the atomic mass of iridium. iridium has two isotopes. iridium - 191 has a mass of 191.0 amu and a percent abundance of 37.58%. iridium - 193 has a mass of 193.0 amu and a percent abundance of 62.42%. show all your work.

Explanation:

Step1: Calculate the contribution of Iridium - 191

The contribution of an isotope to the atomic mass is given by the formula \(m_i\times\frac{\% \text{ abundance}}{100}\), where \(m_i\) is the mass of the isotope.
For Iridium - 191 (\(m_1 = 191.0\) amu and \(\% \text{ abundance}=37.58\%\)), the contribution \(C_1\) is \(191.0\times\frac{37.58}{100}\)

$$C_1=191.0\times0.3758 = 71.7778$$

Step2: Calculate the contribution of Iridium - 193

For Iridium - 193 (\(m_2 = 193.0\) amu and \(\% \text{ abundance}=62.42\%\)), the contribution \(C_2\) is \(193.0\times\frac{62.42}{100}\)

$$C_2=193.0\times0.6242=120.4706$$

Step3: Calculate the atomic mass of Iridium

The atomic mass \(M\) of Iridium is the sum of the contributions of its isotopes, \(M = C_1 + C_2\)

$$M=71.7778+120.4706 = 192.2484\approx192.2$$

Answer:

The atomic mass of iridium is approximately \(192.2\) amu.