Naturally occurring gallium consists of 60.108% Ga-69, with a mess of
samu, and 39.892% Ga - 71, with a mass of 70-9247 amu. Calculate
the average atomic mass of gallium.
Calculate the atomic mass of neon from the given data
Ne=90.913
Ne 0.27
Ne=9.22 step by step plz
Answers
Explanation:
Let the percentage of the isotope
71
G
a
be
=
x
%
Then,
The percentage of the isotope
69
G
a
is
=
(
100
−
x
)
%
We write the mass balance equation
100
⋅
69.72
=
x
⋅
71
+
(
100
−
x
)
⋅
69
6972
=
71
x
+
6900
−
69
x
2
x
=
6972
−
6900
=
72
x
=
36
Therefore,
The percentage of the isotope
71
G
a
is
=
36
%
Answer link
Answer:
find the average atomic mass (Ar) of an element, given the percentage rarities of its isotopes, simply multiply each isotope's Ar by its percentage that is expressed as a decimal and total the results. We can carry this out in a single line of working:
Mr(Ga)=(68.9256⋅0.60108)+(70.9247⋅0.39892)
Mr(Ga)=69.7231 to 4 decimal places
Similarly, you could input the percentages normally and then divide by 100:
Mr(Ga)=(68.9256⋅60.108)+(70.9247⋅39.892)100
Mr(Ga)=69.7231 to 4 decimal places
Notice that the answers are the same. Also observe that the answer is closer to 69 than it is to 71, which makes sense since gallium-69 makes up a greater proportion of gallium in the universe (~60%) than gallium-71 does (~30%).