The answer is b, because all of the other compounds are covelent
<span>"Chemical weathering and physical weathering" would be the correct answer
Chemical weathering breaks down the bonds holding the rocks together, and the physical weathering will crush and break them apart.</span>
The problem you have written you almost have it solved. Take the moles that you have calculated and multiply that by the molecular weight to get the grams.
The STP problem:
use the moles you calculated along with 1 atm for Pressure, and 273 for the temperature and plug into the PV = nRT equation. (also use 0.0821 for R)
From there you can solve for the volume
Hope this helps!
The reaction that has the greatest tendency to be reversed in an spontaneous redox reaction is that whose forward standard reduction potential is the lowest (mos negative) one because that means that the reversed reaction will have the highest (most positive) standard reduction potential.
So, the answer is Cr(3+) + 3e- ---> Cr(s) with Eo = -0.91 V, whose reversed reaction is Cr(s) - 3e- ---> Cr (3+) with Eo = +0.91 V.
Answer: the second option Cr(3+) + 3e- ---> Cr(s) Eo = -0.91 V