Answer:
This is math. by the way read further
So density is equal mass/volume
The units are OK we don't need to change them.
D=126/12.5=10.08 grams per cm^3
Answer 10.08 g/cm^3
Is a stability relative to the elements surrounding it on the periodic table
Answer:
The two-step mechanism is a slow mechanism and a fast mechanism. When we combine them, the result is
2H₂O₂ (aq) ⇒2H₂O (l) + O₂ (g)
Explanation:
We know that the decomposition of hydrogen peroxide is catalyzed by iodide ion, which means that the iodide ion will react with the hydrogen peroxide. There is a slow mechanism and a fast one:
H₂O₂(aq) + I₋(aq) ⇒ H₂O(l) + IO₋(aq) this is the slow reaction
IO₋(aq) + H₂O₂(aq)⇒ H₂O(l) + O₂(g) + I₋ (aq) this is the fast reaction
If we cancel the same type of molecules and ions, the final result is:
2H₂O₂ (aq) ⇒2H₂O (l) + O₂ (g)
This problem is asking for the for pH when a solution of potassium hydroxide is diluted to the double of its initial volume. Thus, the answer turns out to be 11.0.
<h3>pH calculations</h3>
In chemistry, pH calculations are performed based on the following equation relating the pH and the concentration of hydrogen ions in the solution:
![pH=-log([H^+])](https://tex.z-dn.net/?f=pH%3D-log%28%5BH%5E%2B%5D%29)
However, since this problem involves a strong base, KOH as potassium hydroxide, one must calculate the pOH instead, and then convert it to pH with the following equations:
![pOH=-log([OH^-])\\\\pH=14-pOH](https://tex.z-dn.net/?f=pOH%3D-log%28%5BOH%5E-%5D%29%5C%5C%5C%5CpH%3D14-pOH)
In addition, due to the fact it is diluted from 10. mL to 20. mL (with the 10. mL of added distilled water), one needs to use the dilution equation in order to calculate the correct concentration of KOH:
![M_1V_1=M_2V_2\\\\M_2=\frac{M_1V_1}{V_2} \\\\M_2=\frac{0.002M*10.mL}{20.mL}\\ \\M_2=0.001M](https://tex.z-dn.net/?f=M_1V_1%3DM_2V_2%5C%5C%5C%5CM_2%3D%5Cfrac%7BM_1V_1%7D%7BV_2%7D%20%5C%5C%5C%5CM_2%3D%5Cfrac%7B0.002M%2A10.mL%7D%7B20.mL%7D%5C%5C%20%5C%5CM_2%3D0.001M)
Hence, the pOH turns out to be:
![pOH=-log(0.001)=3.0](https://tex.z-dn.net/?f=pOH%3D-log%280.001%29%3D3.0)
And thereby the pH:
![pH=14-3.0\\\\pH=11.0](https://tex.z-dn.net/?f=pH%3D14-3.0%5C%5C%5C%5CpH%3D11.0)
Learn more about pH calculations: brainly.com/question/1195974