Answer:
0.375 M
Explanation:
NaOH(aq) + HBr(aq) ------------> NaBr(aq) + H2O(l)
Concetration of acid CA= 0.250M
Concentration of base CB= ????
Volume of acid VA= 30.0mL
Volume of base VB= 20.0mL
Number of moles of acid nA= 1
Number of moles of base nB= 1
CA VA/CB VB= nA/nB
CB= CAVAnB/VB nA
= 0.25× 30×1/20×1= 0.375 M
Its has 24 protons, 24 electrons, and 28 nuetrons
Answer:
4.96E-8 moles of Cu(OH)2
Explanation:
Kps es the constant referring to how much a substance can be dissolved in water. Using Kps, it is possible to know the concentration of weak electrolytes. Then, pKps is the minus logarithm of Kps.
Now, we know that sodium hydroxide (NaOH) is a strong electrolyte, who is completely dissolved in water. Therefore the pH depends only on OH concentration originating from NaOH. Let us to figure out how much is that OH concentration.
![pH= -log[H]\\pH= -log (\frac{kw}{[OH]})](https://tex.z-dn.net/?f=pH%3D%20-log%5BH%5D%5C%5CpH%3D%20-log%20%28%5Cfrac%7Bkw%7D%7B%5BOH%5D%7D%29)
![8.23 = - log(\frac{Kw}{[OH]} \\10^{-8.23} = Kw/[OH]\\ [OH] = Kw/10^{-8.23}](https://tex.z-dn.net/?f=8.23%20%3D%20-%20log%28%5Cfrac%7BKw%7D%7B%5BOH%5D%7D%20%5C%5C10%5E%7B-8.23%7D%20%3D%20Kw%2F%5BOH%5D%5C%5C%20%5BOH%5D%20%3D%20Kw%2F10%5E%7B-8.23%7D)
![[OH]=1.69E-6](https://tex.z-dn.net/?f=%5BOH%5D%3D1.69E-6)
This concentration of OH affects the disociation of Cu(OH)2. Let us see the dissociation reaction:

In the equilibrum, exist a concentration of OH already, that we knew, and it will be added that from dissociation, called "s":
The expression for Kps is:
![Kps= [Cu^{2+}] [OH]^2](https://tex.z-dn.net/?f=Kps%3D%20%5BCu%5E%7B2%2B%7D%5D%20%5BOH%5D%5E2)
The moles of (CuOH)2 soluble are limitated for the concentration of OH present, according to the next equation.

"s" is the soluble quantity of Cu(OH)2.
The solution for this third grade equation is 
Now, let us calculate the moles in 1 L:

The expression for the Ka for the given acid is:
Ka = [H2P2O7^2-] [H3O+] /[H3P2O7^2-]
<span>Ka is the acid dissociation constant or the acidity constant. It is a measure of the acid strength when in solution. It is an equilibrium constant for the dissociation of the acid.</span>
The choices can be found elsewhere and as follows:
A.) a definite shape and a definite volume
B.) a definite shape but no definite volume
C.) no definite shape and no definite volume
I believe the correct answer is option C. Two basic properties of the gas phase would be it has no definite shape and no definite volume. It takes the shape and volume of its container. Hope this answers the question.