Answer:
A buffer solution is a mixture of two pair salts to maintain a stable pH.
Explanation:
This mixture is made always with a complementary pair of salts (one acid an another basic).
Example:
Acetic Acid (CH3COOH) and Sodium Acetate (NaH3COO).
So when you add a little bit more acid to this mixture, the basic part of the buffer, in this case the Sodium Acetate, will neutralize it and the pH will remain the same.
On the other hand, if the mixture receives some basic substance, the acid part of the buffer, the acetic acid, will neutralize it, so again the pH will remain the same.
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:
Answer:
Sieving
Explanation:
Sieving is a mechanical separation technique which depends on the relative sizes of particles in the mixture.
A mesh is used to discriminate between particle sizes. Particles in the mixture which are larger than the mesh size do not pass through the sieve, hence particles whose size is less than that of the mesh are separated from the rest of the particles in the mixture.
Describe the characteristics of the water at the mountain source:
Answer:
The answer is below
Explanation:
Speed: there will be faster speed due to the steep slope movement of water from the mountain.
Temperature: there will be lower temperatures as a result of the faster speed of water movement which reduces the influence of solar radiation on it.
Oxygen: the oxygen content is higher due to little or no residue particles present in it.
Nutrient Level: this is considered somewhat low as a result of the water coldness and speed which does not support the nutrition base to form.
<span>It describes the true ratio of
atoms in a formula unit. An empirical formula is a formula that gives the
proportions of the elements present in a certain compound however it does not
give the actual numbers or the arrangement of the atoms.</span>
