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:
48%
Explanation:
Based on Gay-Lussac's law, the pressure is directly proportional to the temperature. To solve this question we must assume the temperature increases and all CO2 remains without reaction. The equation is:
P1T2 = P2T1
<em>Where Pis pressure and T absolute temperature of 1, initial state and 2, final state of the gas:</em>
P1 = 10.0atm
T2 = 1420K
P2 = ?
T1 = 730K
P2 = 10.0atm*1420K / 730K
P2 = 19.45 atm
The CO2 reacts as follows:
2CO2 → 2CO+ O2
Where 2 moles of gas react producing 3 moles of gas
Assuming the 100% of CO2 react, the pressure will be:
19.45atm * (3mol / 2mol) = 29.175atm
As the pressure rises just to 24.1atm the moles that react are:
24.1atm * (2mol / 19.45atm) = 2.48 moles of gas are present
The increase in moles is of 0.48 moles, a 100% express an increase of 1mol. The mole percent that descomposes is:
0.48mol / 1mol * 100 = 48%
