Q91P - Chemistry: Molecular Nature Of Matter And Change

Question

Give the systematic names for the formulas or the formulas for the names: 

a.  ${\mathbf{Na}}_{\mathbf{2}}{\mathbf{HPO}}_{\mathbf{4}}$

b.  Potassium carbonate dehydrate;

c.  ${\mathbf{NaNO}}_{\mathbf{2}}$

d.  Ammonium perchlorate

Step-by-Step Solution

Answer

a.  The name of the formula ${\mathbf{Na}}_{\mathbf{2}}{\mathbf{HPO}}_{\mathbf{4}}$  is sodium hydrogen phosphate.

b.  The formula of potassium carbonate dihydrate is ${\mathbf{K}}_{\mathbf{2}}{\mathbf{CO}}_{\mathbf{3}\mathbf{,}}\mathbf{2}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$

c.  The name of the formula ${\mathbf{NaNO}}_{\mathbf{2}}$ is sodium nitrate.

d.  The formula of ammonium perchlorate is ${\mathbf{NH}}_{\mathbf{4}}^{\mathbf{1}\mathbf{-}}{\mathbf{CIO}}_{\mathbf{4}}^{\mathbf{1}\mathbf{-}}\mathbf{\to }{\mathbf{NH}}_{\mathbf{4}}{\mathbf{CIO}}_{{\mathbf{4}}_{}}$

Step 1: Definition of chemical formula

An expression that states the number and type of atoms present in a molecule of a substance is defined as a chemical formula.

Step 2: Explanations

a.  The compound is an ionic compound. The name does not depend on the number of elements. 

${\mathbf{HPO}}_{\mathbf{4}}^{\mathbf{2}\mathbf{-}}$is a polyatomic ion with charge 2^- and known as hydrogen phosphate.

The cation is sodium and the anion is hydrogen phosphate. So it is sodium hydrogen phosphate

 

b.  Carbonate is a polyatomic ion with charge 2^-.Potassium has a charge of +1. The charges will just interchange as the subscripts of these elements

 ${\mathbf{K}}^{\mathbf{1}\mathbf{+}}{\mathbf{CO}}_{\mathbf{3}}^{\mathbf{2}\mathbf{-}}\mathbf{\to }{\mathbf{K}}_{\mathbf{2}}{\mathbf{CO}}_{\mathbf{3}}$

It is also a dihydrate so the ionic compound is attached to 2 water molecules. The formula is  ${\mathbf{K}}_{\mathbf{2}}{\mathbf{CO}}_{\mathbf{3}\mathbf{,}}\mathbf{2}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$

 

c. The compound is an ionic compound. The name does not depend on the number of elements.

${\mathbf{NO}}_{{\mathbf{2}}_{}}$is a polyatomic ion with charge -1 and is known as a nitrate ion.

The cation is sodium So, so it is sodium nitrite.

 

d.  Ammonium is a polyatomic ion with a charge of +1. Perchlorate is a polyatomic ion with charge -1. The charges will just interchange as the subscripts of these elements

 ${\mathbf{NH}}_{\mathbf{4}}^{\mathbf{1}\mathbf{-}}{\mathbf{CIO}}_{\mathbf{4}}^{\mathbf{1}\mathbf{-}}\mathbf{\to }{\mathbf{NH}}_{\mathbf{4}}{\mathbf{CIO}}_{{\mathbf{4}}_{}}$