Answer:
A. 4.5 mol Mg(OH)₂
B. 6 mol NaOH
Explanation:
Let's consider the following balanced equation.
Mg(NO₃)₂ + 2 NaOH ⇒ Mg(OH)₂ + 2 NaNO₃
PART A
The molar ratio of NaOH to Mg(OH)₂ is 2:1. The moles of Mg(OH)₂ produced from 9 moles of NaOH are:
9 mol NaOH × 1 mol Mg(OH)₂/2 mol NaOH = 4.5 mol Mg(OH)₂
PART B
The molar ratio of NaOH to NaNO₃ is 2:2. The moles of NaOH needed to produce 6 moles of NaNO₃ are:
6 mol NaNO₃ × 2 mol NaOH/2 mol NaNO₃ = 6 mol NaOH
Alkaline earth metals are metals of group two. They are divalent metals and they have a highly negative reduction potential hence the metals are mostly extracted by electrolysis.
They are highly reactive metals. They react with water but do so less readily than alkali earth metals.
Owing to their high reactivity, they are seldom found free in nature. They always occur in combined state with other highly reactive nonmetals.
Answer:
C. It does not emit electromagnetic radiation.
Explanation:
Right now, Dark Matter is only a theory. Scientist proposed this to counter some of the strange phenomenon with matter in space.
Scientists know little about dark matter. Some say it's one of the driving forces of the universe. Currently, scientists have no way of measuring or identifying dark matter.
Answer:
Insoluble in water:
Explanation:
Water turns out to be a good solvent for ionic substances, or in general, polarized covalent substances. On the other hand, it is not a good solvent for non-polar substances, these being the vast majority of covalent substances.
Answer:
Concentration of OH⁻:
1.0 × 10⁻⁹ M.
Explanation:
The following equilibrium goes on in aqueous solutions:
.
The equilibrium constant for this reaction is called the self-ionization constant of water:
.
Note that water isn't part of this constant.
The value of
at 25 °C is
. How to memorize this value?
- The pH of pure water at 25 °C is 7.
![[\text{H}^{+}] = 10^{-\text{pH}} = 10^{-7}\;\text{mol}\cdot\text{dm}^{-3}](https://tex.z-dn.net/?f=%5B%5Ctext%7BH%7D%5E%7B%2B%7D%5D%20%3D%2010%5E%7B-%5Ctext%7BpH%7D%7D%20%3D%2010%5E%7B-7%7D%5C%3B%5Ctext%7Bmol%7D%5Ccdot%5Ctext%7Bdm%7D%5E%7B-3%7D)
- However,
for pure water. - As a result,
at 25 °C.
Back to this question.
is given. 25 °C implies that
. As a result,
.