Chapter 3, Problem 3.70QP

(a)

Interpretation Introduction

Interpretation:

Balanced equation for the decomposition of $NaHC{O}_3$ has to be written.

Concept Introduction:

Balanced equation

• Every chemical reaction obliges Law of conservation of mass which states the mass of total amount of the product should be equal to the total mass of the reactants as matter can neither be destroyed nor be created.
• Law of definite proportion states that a chemical compound always contains its constituent elements in a fixed ratio by mass.  It does neither depend on the source of the preparation nor depend on the method of preparation.

Balanced reaction is a chemical reaction in which number of atoms for each element in the reaction and the total charge are same on both reactant side and the product side.

Steps in balancing the information

• Step 1: Write the unbalanced equation
• Step 2: Find the coefficient to balance the equation.
• The coefficient should be reduced to the smallest whole number

(b)

Interpretation Introduction

Interpretation:

The mass of $NaHC{O}_3$ required to produce $20.5g$ of $C{O}_2$ has to be calculated.

Concept Introduction:

• Molar mass of a substance can be calculated from its molecular formula by taking the sum of atomic masses of all the elements present in it.
• Molar mass, number of moles and mass of a substance are related as,

$numberofmoles=\frac{massingrams}{molarmass}$