Answer:
4 and 6
Explanation:
Period 4 has 18 elements and so does period 6.
Answer: 28.1 amu
Explanation:
Mass of isotope 1 = 27.98 amu
% abundance of isotope 1 = 92.21% = 
Mass of isotope 2 = 28.98 amu
% abundance of isotope 2 = 4.70% = 
Mass of isotope 3 = 29.97 amu
% abundance of isotope 2 = 3.09% = 
Formula used for average atomic mass of an element :
![A=\sum[(27.98 )\times 0.922+(28.98)\times 0.047+(29.97)\times 0.0309]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%2827.98%20%29%5Ctimes%200.922%2B%2828.98%29%5Ctimes%200.047%2B%2829.97%29%5Ctimes%200.0309%5D)
Therefore, the average atomic mass of silicon is 28.1 amu
Answer is: concentration ammonia is higher than concentration of ammonium ion.
Chemical reaction of ammonia in water: NH₃ + H₂O → NH₄⁺ + OH⁻.
Kb(NH₃) = 1,8·10⁻⁵.
c₀(NH₃) = 0,8 mol/L.
c(NH₄⁺) = c(OH⁻) = x.
c(NH₃) = 0,8 mol/L - x.
Kb = c(NH₄⁺) · c(OH⁻) / c(NH₃).
0,000018 = x² / 0,8 mol/L - x.
solve quadratic equation: x = c(NH₄⁺) = 3,79·10⁻³ mol/L.
Iodine Strontium Silver...... ..I think.
For the reaction;
N2(g) + O2(g) = 2NO(g)
Kp = pNO²/ pN₂pO₂; (No units)
where;
pNO is the partial pressure of NO;
pN₂ is the partial pressure of nitrogen
pO₂ is the partial pressure of Oxygen
The equilibrium constant Kp is deduced from the balanced chemical equation for a reversible reaction, NOT experimental data as is the case for rate expressions in kinetics.
Kp changes with temperature considerably changing the position of an equilibrium, and, at a constant temperature, and therefore constant K, the position of an equilibrium can change significantly depending on relative concentrations/pressures of 'reactants' and 'products'.
