It is B, and also for a moment I didn't understand that 4.69 x 10^22. I almost did this whole problem wrong.
Answer;
= 0.054 kg or 54 g
Explanation;
Using the equation; Q = mcΔT where Q is the quantity of heat transferred, m is the mass, c is specific heat of the substance, ΔT is delta T, the change in temperature.
ΔT = 75 - 20 = 55 C.
Solve the equation for m
m = Q/ cΔT
Mass = 12500 / (55 × 4200)
= 0.054 kg or 54 g
Answer : The correct option is, 13.7 mole
Solution : Given,
Moles of
= 27.4 moles
The given balanced chemical reaction is,

From the balanced chemical reaction, we conclude that
As, 2 moles of
react with 1 moles of 
So, 27.4 moles of
react with
moles of 
Therefore, the number of moles of oxygen
required are, 13.7 moles
Answer:
34.3 g NH3
Explanation:
M(H2) = 2*1 = 2 g/mol
M(N2) = 2*14 = 28 g/mol
M(NH3) = 14 + 3*1 = 17 g/mol
23.6 g H2* 1 mol/2 g = 11.8 mol H2
28.3 g N2 * 1 mol/28 g = 1.01 mol N2
3H2 + N2 ------> 2NH3
from reaction 3 mol 1 mol
given 11.8 mol 1.01 mol
We can see that H2 is given in excess, N2 is limiting reactant.
3H2 + N2 ------> 2NH3
from reaction 1 mol 2 mol
given 1.01 mol x
x = 2*1.01/1= 2.02 mol NH3
2.02 mol * 17g/1 mol ≈ 34.3 g NH3
Answer:
Coefficients are the numbers in front of the formulas.