Chapter 15, Problem 94A

Interpretation Introduction

Interpretation:

$\text{ΔH}$ is to be calculated using Hess’s Law of two generic reactions..

Concept introduction:

Hess’s law: It states that if two or more thermochemical equations can be added to produce a final equation for a reaction, then the sum of the enthalpy changes for the individual reactions is the enthalpy change for the final reaction.

Answer to Problem 94A

$\text{Atomic}\text{number=Number}\text{of}\text{proton}$

Explanation of Solution

The formula to calculate atomic mass and atomic number is,

${}_{\text{z}}^{}{\text{X}}^{\text{A}}$

$\text{Z=Atomic}\text{number}$

$\text{A=Atomic}\text{mass}$

$\text{Atomic}\text{number=Number}\text{of}\text{proton}$

Suppose, ${}_{\text{19}}^{}{\text{K}}^{\text{40}}$

So, $\text{Atomic}\text{number=Number}\text{of}\text{proton}$

$19=19$

$\text{Neutron=Atomic}\text{mass-Atomic}\text{number}$

$=40-19$

$=21$

Conclusion

Atomic number, proton and neutron can be calculated by the superscript and subscript of any element.