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Question Number 21661 by tawa tawa last updated on 30/Sep/17

Commented by tawa tawa last updated on 30/Sep/17

(1) Oxygen gives three lines in mass spectrometer, indicating the existence of three types of oxygen atom with masses 15.995, 16.999, with relative abundance of 99.76, 0.04 and 0.20 respectively. Determine the relative atomic mass of oxygen (2) An element Y has two isotopes Y_(10) ^(20) and Y_(10) ^(22) present in the ratio of 1:3 respectively, calculate the relative atomic mass of Y (3) The atomic mass of a naturally occuring element is 69.72 a.m.u. The masses of the naturally occuring isotopes are 68.9251 a.m.u for X^(69) and 70.9245 a.m.u. for X^(71) . Calculate the percentage abundance of each isotope and the isotopic ratio of X^(69 ) to X^(71) (4) Naturally occuring lithium consists of two isotopes Li_3 ^6 and Li_(3 ) ^7 with atomic masses 6.0151 and x respectively. If Li_(3 ) ^7 has an abundance of 92.5% and Li_3 ^6 has 7.48%. Calculate the value of x given that the relative atomic mass of the atom is 6.940.

$$\left(\mathrm{1}\right) \\ $$$$\mathrm{Oxygen}\:\mathrm{gives}\:\mathrm{three}\:\mathrm{lines}\:\mathrm{in}\:\mathrm{mass}\:\mathrm{spectrometer},\:\mathrm{indicating}\:\mathrm{the}\:\mathrm{existence}\:\mathrm{of} \\ $$$$\mathrm{three}\:\mathrm{types}\:\mathrm{of}\:\mathrm{oxygen}\:\mathrm{atom}\:\mathrm{with}\:\mathrm{masses}\:\mathrm{15}.\mathrm{995},\:\mathrm{16}.\mathrm{999},\:\mathrm{with}\:\mathrm{relative} \\ $$$$\mathrm{abundance}\:\mathrm{of}\:\mathrm{99}.\mathrm{76},\:\mathrm{0}.\mathrm{04}\:\mathrm{and}\:\mathrm{0}.\mathrm{20}\:\mathrm{respectively}.\:\mathrm{Determine}\:\mathrm{the}\:\mathrm{relative}\: \\ $$$$\mathrm{atomic}\:\mathrm{mass}\:\mathrm{of}\:\mathrm{oxygen} \\ $$$$ \\ $$$$\left(\mathrm{2}\right) \\ $$$$\mathrm{An}\:\mathrm{element}\:\mathrm{Y}\:\mathrm{has}\:\mathrm{two}\:\mathrm{isotopes}\:\mathrm{Y}_{\mathrm{10}} ^{\mathrm{20}} \:\mathrm{and}\:\mathrm{Y}_{\mathrm{10}} ^{\mathrm{22}} \:\mathrm{present}\:\mathrm{in}\:\mathrm{the}\:\mathrm{ratio}\:\mathrm{of}\:\mathrm{1}:\mathrm{3}\:\mathrm{respectively}, \\ $$$$\mathrm{calculate}\:\mathrm{the}\:\mathrm{relative}\:\mathrm{atomic}\:\mathrm{mass}\:\mathrm{of}\:\mathrm{Y} \\ $$$$ \\ $$$$\left(\mathrm{3}\right) \\ $$$$\mathrm{The}\:\mathrm{atomic}\:\mathrm{mass}\:\mathrm{of}\:\mathrm{a}\:\mathrm{naturally}\:\mathrm{occuring}\:\mathrm{element}\:\mathrm{is}\:\mathrm{69}.\mathrm{72}\:\mathrm{a}.\mathrm{m}.\mathrm{u}.\:\mathrm{The}\:\mathrm{masses}\: \\ $$$$\mathrm{of}\:\mathrm{the}\:\mathrm{naturally}\:\mathrm{occuring}\:\mathrm{isotopes}\:\mathrm{are}\:\mathrm{68}.\mathrm{9251}\:\mathrm{a}.\mathrm{m}.\mathrm{u}\:\mathrm{for}\:\:\mathrm{X}^{\mathrm{69}} \:\mathrm{and}\:\mathrm{70}.\mathrm{9245}\: \\ $$$$\mathrm{a}.\mathrm{m}.\mathrm{u}.\:\mathrm{for}\:\mathrm{X}^{\mathrm{71}} .\:\mathrm{Calculate}\:\mathrm{the}\:\mathrm{percentage}\:\mathrm{abundance}\:\mathrm{of}\:\mathrm{each}\:\mathrm{isotope}\:\mathrm{and}\:\mathrm{the} \\ $$$$\mathrm{isotopic}\:\mathrm{ratio}\:\mathrm{of}\:\mathrm{X}^{\mathrm{69}\:} \mathrm{to}\:\mathrm{X}^{\mathrm{71}} \\ $$$$ \\ $$$$\left(\mathrm{4}\right) \\ $$$$\mathrm{Naturally}\:\mathrm{occuring}\:\mathrm{lithium}\:\mathrm{consists}\:\mathrm{of}\:\mathrm{two}\:\mathrm{isotopes}\:\:\mathrm{Li}_{\mathrm{3}} ^{\mathrm{6}} \:\mathrm{and}\:\mathrm{Li}_{\mathrm{3}\:} ^{\mathrm{7}} \mathrm{with}\:\mathrm{atomic} \\ $$$$\mathrm{masses}\:\mathrm{6}.\mathrm{0151}\:\mathrm{and}\:\mathrm{x}\:\mathrm{respectively}.\:\mathrm{If}\:\mathrm{Li}_{\mathrm{3}\:} ^{\mathrm{7}} \mathrm{has}\:\mathrm{an}\:\mathrm{abundance}\:\mathrm{of}\:\mathrm{92}.\mathrm{5\%}\:\mathrm{and}\: \\ $$$$\mathrm{Li}_{\mathrm{3}} ^{\mathrm{6}} \:\mathrm{has}\:\mathrm{7}.\mathrm{48\%}.\:\mathrm{Calculate}\:\mathrm{the}\:\mathrm{value}\:\mathrm{of}\:\mathrm{x}\:\mathrm{given}\:\mathrm{that}\:\mathrm{the}\:\mathrm{relative}\:\mathrm{atomic}\:\mathrm{mass} \\ $$$$\mathrm{of}\:\mathrm{the}\:\mathrm{atom}\:\mathrm{is}\:\mathrm{6}.\mathrm{940}. \\ $$

Commented by tawa tawa last updated on 30/Sep/17

please help. God bless you.

$$\mathrm{please}\:\mathrm{help}.\:\mathrm{God}\:\mathrm{bless}\:\mathrm{you}. \\ $$

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