Answer:
V = 36.7L of 
Explanation:
1. Write the chemical reaction for the decomposition of sodium azide:

2. Find the number of moles of
produced by the decomposition of 71.4g of
:

3. Use the ideal gas equation to find the Volume of
occupied by 1.65 moles of
, at the temperature and pressure given by the problem:

Solving for V:

Converting the temperature from ◦C to K:
25◦C+273.15=298.15K
Replacing values:

V=36.7L of 
Answer:
2.55 moles
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
O valence electron number is the answer