Answer:

Explanation:
Hello,
In this case, since we can consider hydrogen gas as an ideal gas, we check the volume-pressure-temperature-mole relationship by using the ideal gas equation:

Whereas we are asked to compute the moles given the temperature in Kelvins, thr pressure in atm and volume in L as shown below:

Best regards.
<u>Answer:</u> The pH of the solution is 11.24
<u>Explanation:</u>
We are given:
Molarity of ammonia = 0.2 M

The given chemical equation follows:

I: 0.2
C: -x +x +x
E: 0.2-x x x
The expression for equilibrium constant follows:
![K_b=\frac{[NH_4^+][OH^-]}{[NH_3]}](https://tex.z-dn.net/?f=K_b%3D%5Cfrac%7B%5BNH_4%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BNH_3%5D%7D)
Putting values in above expression, we get:

Neglecting the negative value of x as concentration cannot be negative.
So, ![[OH^-]=x=1.88\times 10^{-3}M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3Dx%3D1.88%5Ctimes%2010%5E%7B-3%7DM)
pOH is defined as the negative logarithm of hydroxide ion concentration present in the solution.
![pOH=-\log [OH^-]](https://tex.z-dn.net/?f=pOH%3D-%5Clog%20%5BOH%5E-%5D)
Putting values in above equation, we get:

We know:

Hence, the pH of the solution is 11.24
Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2."
Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...
Hopefully this has helped! :)
Answer:
This is a simple case of ratios. (1 mol)/(22.4 L)=(n mol)/(.025 L) Then we cross multiply and we get 22.4n=.025 We divide each side by 22.4 to find n=.001116 mol Then to convert the moles to atoms we multiply, and cross-cancel the units (.001116 mol)/1 xx (6.02 xx 10^23 atms)/(1 mol) and we have 6.72 xx 10^20 atoms. I've found the trick of cross-cancelling units to be a very effective mnemonic, it always makes sure you carry out the correct calculation to find the desired units.
Explanation: