Chapter 4, Problem 41QRT

(a)

Interpretation Introduction

Interpretation:

The sign of work done for reaction between $F{e}_2{S}_3{\text{ and HNO}}_{\text{3}}$ has to be identified.

Concept Introduction:

The first law of thermodynamics states that energy can be either destroyed or created but instead it can be converted from one form to other.

The equation for the first law of thermodynamics can be given as,

  $\text{ΔU = q + w}$

Here,

$\text{ΔU =}$ Change in internal energy

$\text{q =}$ Heat

$\text{w =}$ Work

• If system gains heat, then $\text{q}$= positive.
• If work is done on the system, then $\text{w}$= positive.
• If system loses heat, then $\text{q}$= negative.
• If work is done by the system, then $\text{w}$= negative.

(b)

Interpretation Introduction

Interpretation:

The sign of work done for reaction between $C_3{H}_8{\text{ and O}}_{\text{2}}$ has to be identified.

Concept Introduction:

The first law of thermodynamics states that energy can be either destroyed or created but instead it can be converted from one form to other.

The equation for the first law of thermodynamics can be given as,

  $\text{ΔU = q + w}$

Here,

$\text{ΔU =}$ Change in internal energy

$\text{q =}$ Heat

$\text{w =}$ Work

• If system gains heat, then $\text{q}$= positive.
• If work is done on the system, then $\text{w}$= positive.
• If system loses heat, then $\text{q}$= negative.
• If work is done by the system, then $\text{w}$= negative.