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) :)
Answer:
A = 349 g.
Explanation:
Hello there!
In this case, since the radioactive decay kinetic model is based on the first-order kinetics whose integrated rate law is:
We can firstly calculate the rate constant given the half-life as shown below:
Therefore, we can next plug in the rate constant, elapsed time and initial mass of the radioactive to obtain:
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Answer:
pH = 2.0
Explanation:
To find the pH of a solution, take the -log[H+]. In this case, the -log(9.4 x 10^-3) equals 2.02687 which makes 2.0 when accounting for significant figures.
