Chapter 7, Problem 7.51P

Interpretation Introduction

(a)

Interpretation:

The reference temperature used as the basis for the enthalpy formula is to be determined.

Concept introduction:

Reference temperature is the temperature used as the basis for any calculations or to derive any formula.

Interpretation Introduction

(b)

Interpretation:

The final temperature of the flask contents is to be calculated.

Concept introduction:

A flowchart is the complete representation of a process through boxes or other shapes which represents process units and arrows that represents the input and output of the process. The flowchart must be fully labelled to infer important data about the process involved.

In a system, a conserved quantity (total mass, mass of a particular species, energy or momentum) is balanced and can be written as:

$input+generation-output-consumpumtion=accumulation$

Here, ‘ input’ is the stream which enters the system. ‘ generation’ is the term used for the quantity that is produced within the system. ‘ output’ is the stream which leaves the system. ‘ consumption’ is the term used for the quantity that is consumed within the system. ‘ accumulation’ is used for the quantity which is builds up within the system.

All the equations which are formed are then solved simultaneously to calculate the values of the unknown variables.

Formula for heat, $Q$ is given by:

$Q=m\text{c}\Delta T$   ....... (2)

Here, $m$ is the mass of the substance, $\text{c}$ is the specific heat capacity of the substance at a particular temperature and $\Delta T$ is the change in the temperature of the substance.

Interpretation Introduction

(c)

Interpretation:

The final temperature of the flask is to be determined in accordance with the value calculated in part (b), if some of the water is evaporated on contact with the hot iron.

Concept introduction:

Saturated steam is the steam vaporized with little heat at its boiling point. Above this saturation temperature, the steam becomes superheated.

At this saturation temperature at a particular pressure, steam is present along with some condensed steam when cooled.