Unfortunately, you haven't shared any data list which would make braunly users able to help you. The only thing I can suggest you is to write the neutralization reactions, this can make you understand the calculations more or less clearly. Please, next time check your attachments carefully.
Answer: [N2]₀ = 10M and [H2]₀ = 11M
Explanation: To calculate the initial concentration, you would have to set up an ICE table, which is an organized way of tracking known quantities or the ones you want to find. ICE stands for:
I is initial amount;
C is change in concentration;
E is for equilibrium concentration;
For the mixture,
N2 3H2 2NH3
I [N2]₀ [H2]₀ 0
C - x -3x +2x
E [N2]₀ - x =8 [H2]₀ - 3x =5 2x =4
With the product, we can find "x":
2x=4
x=2M
With x=2, find the concentrations:
[N2]₀ - x = 8
[N2]₀ = 10M
[H2]₀ - 3x = 5
[H2]₀ = 11M
The initial concentrations of nitrogen gas [N2] is 10.0 M and of hydrogen gas [H2] is 11.0 M.
Answer:
5.25 moles.
Explanation:
The decomposition reaction of NaN₃ is as follows :

We need to find how many grams of N₂ produced in the process.
From the above balanced chemical reaction, we conclude that the ratio of moles of sodium azide and nitrogen gas are 2 : 3.
2 moles of sodium azide decomposes to give 3 moles of nitrogen gas. So,
3.5 moles of sodium azide decomposes to give
moles of nitrogen gas.
Hence, the number of moles produced is 5.25 moles.
C. NO2 is covalent. Hope this helps!
You are actually giving 5 points. Ps I just got five points for telling you that