Answer:
The effective nuclear charge for a 2nd row electron in Sulfur is +8
Explanation:
Zeff = Z (# of protons) - S (# of shielded electrons)
Since there are 8 electrons in the first and second rows combined, there are 8 shielding electrons.
The number of protons in Sulfur is 16.
Therefore,
Zeff = 16 - 8
Zeff = 8
(It's been awhile, so I am not 100% sure)
Answer:
pH = 11.216.
Explanation:
Hello there!
In this case, according to the ionization of ammonia in aqueous solution:
We can set up its equilibrium expression in terms of x as the reaction extent equal to the concentration of each product at equilibrium:
![Kb=\frac{[NH_4^+][OH^-]}{[NH_3]} \\\\1.80x10^{-5}=\frac{x*x}{0.150-x}](https://tex.z-dn.net/?f=Kb%3D%5Cfrac%7B%5BNH_4%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BNH_3%5D%7D%20%5C%5C%5C%5C1.80x10%5E%7B-5%7D%3D%5Cfrac%7Bx%2Ax%7D%7B0.150-x%7D)
However, since Kb<<<1 we can neglect the x on bottom and easily compute it via:
Which is also:
![[OH^-]=1.643x10^{-3}M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D1.643x10%5E%7B-3%7DM)
Thereafter we can compute the pOH first:
Finally, the pH turns out:
Regards!
Answer:
0.20 mol
Explanation:
Let's consider the reduction of iron from an aqueous solution of iron (II).
Fe²⁺ + 2 e⁻ ⇒ Fe
The molar mass of Fe is 55.85 g/mol. The moles corresponding to 5.6 g of Fe are:
5.6 g × 1 mol/55.85 g = 0.10 mol
2 moles of electrons are required to deposit 1 mole of Fe. The moles of electrons required to deposit 0.10 moles of Fe are
0.10 mol Fe × 2 mol e⁻/1 mol Fe = 0.20 mol e⁻
The density would be the same for the whole bar as well as one half of the bar. Density is a identity I believe, by this I mean that it stays the same no matter how little or how much of the same substance you have. Since density = mass / volume, half the bar has half of the weight as well as half of the volume of the whole bar, making the density the same.
For example, a block weighs 10 grams and has a volume of 5 ml. the density would be d = 10/5 or, d = 2g/ml
Half of the block weighs 5 grams and has a volume of 2.5 ml. The density is d = 5/2.5, or, d = 2 g/ml.
See, although there are different amounts of the same substance, their density is the same.
