Question

A triatomic molecule can be modelled as three rigid sphere joined by three rigid rods forming an triangle. Consider a triatomic gas consisting such molecule. If gas performs 30 J work when it expands under constant pressure the heat given to gas is –

• A. 60 J
• B. 30 J
• C. 45 J
• D. 120 J

Answer 1

Answer: (D)

120 J

Answer 2

$\frac{\Delta Q}{W}$ = $\frac{C_{P}}{R}$

C_P = $\left( \frac{f}{2} + 1 \right)$ R

(f = degree of produce)

= 4R

\ DQ = 4W = 120 J