Chapter 7.2, Problem 3RQ

Interpretation Introduction

Interpretation :

Difference between a coefficient and subscripts in a chemical must be explained with examples of each.

Concept Introduction :

In chemical equation formula of compounds are given along with the physical states. Coefficients and subscripts can be found in chemical equation. Coefficients are the number written before each species and subscripts are the numbers written for all the elements in a compound.

Answer to Problem 3RQ

A coefficients represents the number of moles of the species whereas a subscript represents the number of a particular atoms present per molecule.

Explanation of Solution

Coefficients in chemical reaction give the idea of mole ratio in which the reaction is taking place. But the subscripts gives idea of how many particular type of atoms is there in a molecule.

  ${\text{CaCO}}_{\text{3}}{\text{(s)+2HNO}}_{\text{3}}\text{(aq)}\to {\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}{\text{(aq)+CO}}_{\text{2}}{\text{(g)+H}}_{\text{2}}\text{O(l)}\text{.}$

In this reaction it is clear that 2 moles of HNO₃ is required per mole of CaCO₃. Thus coefficient of HNO₃ is 2. ‘3’ in HNO₃ is the subscript of O which represents that there are 3 O atoms in 1 HNO₃ molecule.