Isotopes are atoms of the same element that have different masses. The relative atomic mass (am) is a weighted average that takes into account the abundance of each isotope. We can calculate the relative atomic mass using the following expression.

where,
- abi: percent abundance of each isotope
For Gallium,
[1]
where "x" and "y" are the unknown abundances.
We also know that the sum of both abundances must be 100%.
x + y = 100
y = 100 - x [2]
If we replace [2] in [1], we get

Then, in [2]
y = 100 - x = 100 - 20.5 = 79.5
In conclusion, Ga-69 has an abundance of 20.5% and Ga-71 has an abundance of 79.5%.
You can learn more about isotopes in: brainly.com/question/21536220?referrer=searchResults
Answer:
[CO] = 0.078M
[Cl2] = 0.078M
[COCl2] = 0.477M
Explanation:
Based on the reaction:
CO(g) Cl2(g) ⇄ COCl2(g)
<em>Where equilibrium constant, kc, is:</em>
kc = 77.5 = [COCl2] / [CO] [Cl2]
[] represents the equilibrium concentration of each gas. The initial concentration of each gas is:
[CO] = 0.555mol/1.00L = 0.555M
[Cl2] = 0.555M
And equilibrium concentrations are:
[CO] = 0.555M - x
[Cl2] = 0.555M - x
[COCl2] = x
<em>Where x is reaction coordinate</em>
Replacing in kc expression:
77.5 = [x] / [0.555M - x] [0.555M - x]
77.5 = x / 0.308025 - 1.11 x + x²
23.8719 - 86.025 x + 77.5 x² = x
23.8719 - 87.025 x + 77.5 x² = 0
x = 0.477M. Right answer
x = 0.646M. False answer. Produce negative concentrations
Replacing:
<h3>[CO] = 0.555M - 0.477M = 0.078M</h3><h3>[Cl2] = 0.078M</h3><h3>[COCl2] = 0.477M</h3>
And those concentrations are the equilibrium concentrations
Crystallization is the correct answer for recovering salt from a solution by evaporating the solvent