3Si + 2N2 --> Si3N4 (as given)
n(Si) = m/MM = 38.25/28.085 = 1.3619 mol
n(N2) = 14.33/2*14.007 = 0.5115 mol
Therefore, N2 is limiting and Si is in excess
The molar ratio of 2N2:Si3N4 is 2:1
So, 0.0575 mol of silicon nitride is formed (dividing 0.5115 by 2)
m of silicon nitride= n*mm = 0.0575*140.283 = 8.06627... g
= 8.066g (4 significant figures)
(hopefully it is right, but double check in case i did something wrong) :)
There are 4 significant figures! Start counting after the first non-zero digit :)
Hope this helps.
Answer:
The pH decreases.
Explanation:
Hello,
In organic chemistry, oxidation accounts for either the increasing of C-O bonds or the increasing in the oxygen atoms into the molecule. Thus, if we consider the oxidation from benzyl alcohol to benzoic acid, there will be a carboxyl functional group instead of a hydroxile one. Now, the presence of the polar -O-H bonds that are ionizable, there will be a
releasing causing the pH to decrease (increase acidity).
Regards.
Answer: option A.
A physical change occurred in which the iron remained iron, but lost one of its physical properties
Explanation: magnetization and demagnetization is a physical change as no new substance is form and it is easily reversed. When an iron rod is magnetized, it can loss it magnetic property by hitting it. So when an iron rod which is magnetized falls from a height it can also loss its magnetic property