Hey there! The answer to your first question is SILICON, Nickle has 28 protons, silicon has 14, 14+14=28. Its the only element thats adds up. I dont know about the 2nd one myself.
0.500 moles is roughly .5*6.022*10^23=3.011*10^23 atoms. This is independent of STP.
Answer:
energy, in physics, the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. There are, moreover, heat and work—i.e., energy in the process of transfer from one body to another. ... For example, any given body has kinetic energy if it is in motion.
Explanation:
please mark my answer in brainlist
Answer:
(a) 
(b) 
(c) 
(d) 
Explanation:
Hello,
In this case, given the solubility of each salt, we can compute their molar solubilities by using the molar masses. Afterwards, by using the mole ratio between ions, we can compute the concentration of each dissolved and therefore the solubility product:
(a) 

In such a way, as barium and selenate ions are in 1:1 molar ratio, they have the same concentration, for which the solubility product turns out:
![Ksp=[Ba^{2+}][SeO_4^{2-}]=(6.7x10^{-4}\frac{mol}{L} )^2\\\\Ksp=4.50x10^{-7}](https://tex.z-dn.net/?f=Ksp%3D%5BBa%5E%7B2%2B%7D%5D%5BSeO_4%5E%7B2-%7D%5D%3D%286.7x10%5E%7B-4%7D%5Cfrac%7Bmol%7D%7BL%7D%20%20%20%29%5E2%5C%5C%5C%5CKsp%3D4.50x10%5E%7B-7%7D)
(B) 

In such a way, as barium and bromate ions are in 1:2 molar ratio, bromate ions have twice the concentration of barium ions, for which the solubility product turns out:
![Ksp=[Ba^{2+}][BrO_3^-]^2=(7.30x10^{-3}\frac{mol}{L})(3.65x10^{-3}\frac{mol}{L})^2\\\\Ksp=1.55x10^{-6}](https://tex.z-dn.net/?f=Ksp%3D%5BBa%5E%7B2%2B%7D%5D%5BBrO_3%5E-%5D%5E2%3D%287.30x10%5E%7B-3%7D%5Cfrac%7Bmol%7D%7BL%7D%29%283.65x10%5E%7B-3%7D%5Cfrac%7Bmol%7D%7BL%7D%29%5E2%5C%5C%5C%5CKsp%3D1.55x10%5E%7B-6%7D)
(C) 

In such a way, as ammonium, magnesium and arsenate ions are in 1:1:1 molar ratio, they have the same concentrations, for which the solubility product turns out:
![Ksp=[NH_4^+][Mg^{2+}][AsO_4^{3-}]^2=(1.31x10^{-4}\frac{mol}{L})^3\\\\Ksp=2.27x10^{-12}](https://tex.z-dn.net/?f=Ksp%3D%5BNH_4%5E%2B%5D%5BMg%5E%7B2%2B%7D%5D%5BAsO_4%5E%7B3-%7D%5D%5E2%3D%281.31x10%5E%7B-4%7D%5Cfrac%7Bmol%7D%7BL%7D%29%5E3%5C%5C%5C%5CKsp%3D2.27x10%5E%7B-12%7D)
(D) 

In such a way, as the involved ions are in 2:3 molar ratio, La ion is twice the molar solubility and MoOs ion is three times it, for which the solubility product turns out:
![Ksp=[La^{3+}]^2[MoOs^{-2}]^3=(2*1.58x10^{-5}\frac{mol}{L})^2(3*1.58x10^{-5}\frac{mol}{L})^3\\\\Ksp=1.05x10^{-22}](https://tex.z-dn.net/?f=Ksp%3D%5BLa%5E%7B3%2B%7D%5D%5E2%5BMoOs%5E%7B-2%7D%5D%5E3%3D%282%2A1.58x10%5E%7B-5%7D%5Cfrac%7Bmol%7D%7BL%7D%29%5E2%283%2A1.58x10%5E%7B-5%7D%5Cfrac%7Bmol%7D%7BL%7D%29%5E3%5C%5C%5C%5CKsp%3D1.05x10%5E%7B-22%7D)
Best regards.
It is true because it changes the identity of a persin or a character