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Two stable isotopes of lithium \(^6 3\mathit{Li}\) and \(^73\mathit{li}\) have respective abundances of \(7.5\%\) and \(92.5\%\).These isotopes haveQuestion: Two stable isotopes of lithium ^6 3mathit{Li} and ^73mathit{li} have respective abundances of 7.5% and 92.5%.These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium. masses \(6.01512 u \)and \(7.01600 u\), respectively. Find the atomic mass of lithium.

Answer

Mass of \(^6 3\mathit{Li}\),\(m_1=6.01512u\)
Mass of \(^73\mathit{Li}\), \(m_2=7.01600u\)
Abundances of the following are \(n_1=7.5%\) and \(n_2=92.5%\)
Atomic mass of \(Li\) is given by= \(\frac{m_1n_1+m_1n_1}{m_1+m_2}\)
= \(\frac{6.01512\times 7.5+7.01600\times 92.5}{6.01512+7.01600}\)
The atomic number of \( Li\) is \(6.9409344u\).
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