(a) The work done by the nitrogen against external pressure is 126.66 J.
(b) The change in the internal energy of the system is -2,466.66 J.
The given parameters:
The molar mass of the given compound is calculated as follows;
NaN₃ = 23+ (14 x 3) = 65 g/mol
65 g -------------- 42
2.25 g ------------- ?
[tex]= \frac{2.25 \times 42}{65} \\\\= 1.45 \ g[/tex]
The volume of the nitrogen gas is calculated as follows;
[tex]\rho = \frac{m}{V} \\\\V = \frac{m}{\rho} \\\\V = \frac{1.45}{1.165} \\\\V = 1.25 \ L[/tex]
[tex]V = 0.00125 \ m^3[/tex]
The work done by the nitrogen against external pressure is calculated as follows;
[tex]W = PV\\\\W = 101325 \times 0.00125\\\\W = 126.66 \ J[/tex]
The change in the internal energy of the system is calculated by applying first law of thermodynamics as follows;
[tex]\Delta E = Q - W\\\\\Delta E = (-2,340) - (126.66)\\\\\Delta E = -2,466.66 \ J[/tex]
Learn more about first law of thermodynamics here: https://brainly.com/question/2965070
