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
Technically, the answer should be 3.30 * 10^23 grams. But I think you mean either molecules, atoms, moles or grams of Ni2I6 with that number of molecules .
1 mole of Ni2 I6 = 6.02 * 10^23 molecules
x [mole] = 3.30 * 10^23 molecules
1/x = 6.02 * 10^23 / 3.30 * 10^23 Cancel the 10^23 on the right side
1/x = 6.02 / 3.30 Cross multiply
3.30 = 6.02 x Divide by 6.02
3.30 / 6.02 = x
x = 0.548 moles
what to do from here?
1 mole of Ni2I6 is
2 * Ni = 2 * 59 = 118 grams
6 * I = 6 * 131 = <u>786 grams</u>
Total = 904 grams
Set up a proportion.
<u>1 mole Ni2I6 </u> = <u>904 grams</u>
0.548 moles = x
1/0.548 = 904/x Cross multiply
x = 0.548 * 904
x = 495.4 grams of Ni2I6 <<<<<< Answer.
Answer:

Explanation:
The expression for the root mean square speed is:
R is Gas constant having value = 8.314 J / K mol
M is the molar mass of gas
Molar mass of water vapor = 18.0 g/mol = 0.018 kg/mol
Temperature = ?
m/s

The correct answer is 2.
In oxidation-reduction reactions (or redox reactions), a number of electrons are transferred between two species. During this process, the oxidation number of an atom (or molecule or ion) changes by receiving or losing an electron.
The average kinetic energy and thermal energy decreases, and the temperature decreases as well.