Chapter U1.7, Problem 5E

Interpretation Introduction

(a)

Interpretation:

The phase of each compound that is baking soda, vinegar and carbon dioxide needs to be determined.

Concept introduction:

Chemistry deals with the different processes which occur in surrounding and is directly or indirectly related with each other.

Different changes taking place in the environment can be physical and chemical on the basis of change in physical state and chemical composition of the matter.

Physical changes are related to change in the physical state of the substance whereas the chemical change is associated with change in chemical composition that results the formation of new chemical substance/s.

Answer to Problem 5E

• ${\text{NaHCO}}_{\text{3}}$=solid phase
• ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}{\text{O}}_{\text{2}}$ = Liquid phase
• ${\text{CO}}_{\text{2}}$ = Gas phase

Explanation of Solution

When baking soda ( ${\text{NaHCO}}_{\text{3}}$ ) is mixed with vinegar ( ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}{\text{O}}_{\text{2}}$ ), it forms a colorless liquid with bubbles of ${\text{CO}}_{\text{2}}$. Hence, the physical phase of baking soda is solid, vinegar is liquid state and that ${\text{CO}}_{\text{2}}$ is gas.

Interpretation Introduction

(b)

Interpretation:

Whether the change is physical or chemical needs to be identified.

Concept introduction:

Chemistry deals with the different processes which occur in surrounding and is directly or indirectly related with each other.

Different changes taking place in the environment can be physical and chemical on the basis of change in physical state and chemical composition of the matter.

Physical changes are related to change in the physical state of the substance whereas the chemical change is associated with change in chemical composition that results the formation of new chemical substance/s.

Answer to Problem 5E

Chemical change.

Explanation of Solution

A chemical change is associated with the formation of new substance having different chemical composition from the reactant molecules. When baking soda ( ${\text{NaHCO}}_{\text{3}}$ ) is mixed with vinegar ( ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}{\text{O}}_{\text{2}}$ ), it forms a colorless liquid with bubbles of ${\text{CO}}_{\text{2}}$. Here new substance that is ${\text{CO}}_{\text{2}}$ gas is formed with a colorless liquid of sodium acetate therefore it is a chemical change. Thus, the formation of new substances in this change makes it a chemical change.

(c)

Interpretation Introduction

Interpretation:

The position of sodium before and after the change needs to be explained.

Concept introduction:

Chemistry deals with the different processes which occur in surrounding and is directly or indirectly related with each other.

Different changes taking place in the environment can be physical and chemical on the basis of change in physical state and chemical composition of the matter.

Physical changes are related to change in the physical state of the substance whereas the chemical change is associated with change in chemical composition that results the formation of new chemical substance/s.

Answer to Problem 5E

Sodium remains in the solution in the form of Na + ions.

Explanation of Solution

When baking soda ( ${\text{NaHCO}}_{\text{3}}$ ) is mixed with vinegar ( ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}{\text{O}}_{\text{2}}$ ), it forms a colorless liquid with bubbles of ${\text{CO}}_{\text{2}}$. In this chemical change the chemical reaction can be written as follows:

${\text{NaHCO}}_{\text{3}}\left(s\right){\text{+ C}}_{\text{2}}{\text{H}}_{\text{4}}{\text{O}}_{\text{2}}\left(aq\right)\stackrel{}{\to }{\text{NaC}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\left(aq\right){\text{+ CO}}_{\text{2}}\left(g\right){\text{+ H}}_{\text{2}}\text{O}\left(l\right)$

Since, NaHCO₃ was initially present in the solid state which is mixed with aqueous solution of vinegar. The product formed in the reaction is sodium acetate, carbon dioxide and water. The sodium acetate is present in a soluble form here thus; sodium will be present in the form of ions in the solution.