Answer:
C
Noble gases are the least reactive of all elements. That's because they have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds. The noble gases are the least reactive of any elements on the periodic table.All of the elements in Group Zero are noble gases. The list includes helium, neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). They are also called inert gases because they do not react with other elements of periodic table. The reason behind their inertness is that their outermost shell is complete and they do not have the tendency to lose or gain electrons.
I think the answer is 2/5 or 0.4
Answer:
3.0×10⁻¹³ M
Explanation:
The solubility product Ksp is the product of the concentrations of the ions involved. This relation can be used to find the solubility of interest.
<h3>Equation</h3>
The power of each concentration in the equation for Ksp is the coefficient of the species in the balanced equation.
Ksp = [Al₃⁺³]×[OH⁻]³
<h3>Solving for [Al₃⁺³]</h3>
The initial concentration [OH⁻] is that in water, 10⁻⁷ M. The reaction equation tells us there are 3 OH ions for each Al₃ ion. If x is the concentration [Al₃⁺³], then the reaction increases the concentration [OH⁻] by 3x.
This means the solubility product equation is ...
Ksp = x(10⁻⁷ +3x)³
For the given Ksp = 3×10⁻³⁴, we can estimate the value of x will be less than 10⁻⁸. This means the sum will be dominated by the 10⁻⁷ term, and we can figure x from ...
3.0×10⁻³⁴ = x(10⁻⁷)³
Then x = [Al₃⁺³] will be ...
![[\text{Al}_3^{\,+3}]=\dfrac{3.0\times10^{-34}}{10^{-21}}\approx \boxed{3.0\times10^{-13}\qquad\text{moles per liter}}](https://tex.z-dn.net/?f=%5B%5Ctext%7BAl%7D_3%5E%7B%5C%2C%2B3%7D%5D%3D%5Cdfrac%7B3.0%5Ctimes10%5E%7B-34%7D%7D%7B10%5E%7B-21%7D%7D%5Capprox%20%5Cboxed%7B3.0%5Ctimes10%5E%7B-13%7D%5Cqquad%5Ctext%7Bmoles%20per%20liter%7D%7D)
We note this value is significantly less than 10⁻⁷, so our assumption that it could be neglected in the original Ksp equation is substantiated.
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<em>Additional comment</em>
The attachment shows the solution of the 4th-degree Ksp equation in x. The only positive real root (on the bottom line) rounds to 3.0×10^-13.
Answer:
30100000000000000000 atoms
Explanation:
Ar of Fe : 56
0.028/56 = 0.0005 moles of Fe
0.0005 * 6.02 * 10^23(Avagardro's law of constant)
= 3.01*10^20 atoms