4.2 Classifying chemical reactions  (Page 9/34)

Use the following equations to answer the next five questions:

i. ${\text{H}}_2\text{O}(s)⟶{\text{H}}_2\text{O}(l)$

ii. ${\text{Na}}^{\text{+}}(aq)+{\text{Cl}}^{\text{−}}(\text{aq})+{\text{Ag}}^{\text{+}}(aq)+{\text{NO}}_3{}^{\text{−}}(aq)⟶\text{AgCl}(s)+{\text{Na}}^{\text{+}}(aq)+{\text{NO}}_3{}^{\text{−}}(aq)$

iii. ${\text{CH}}_3\text{OH}(g)+{\text{O}}_2(g)⟶{\text{CO}}_2(g)+{\text{H}}_2\text{O}(g)$

iv. $2{\text{H}}_2\text{O}(l)⟶2{\text{H}}_2(g)+{\text{O}}_2(g)$

v. ${\text{H}}^{\text{+}}(aq)+{\text{OH}}^{\text{−}}(aq)⟶{\text{H}}_2\text{O}(l)$

(a) Which equation describes a physical change?

(b) Which equation identifies the reactants and products of a combustion reaction?

(c) Which equation is not balanced?

(d) Which is a net ionic equation?

Indicate what type, or types, of reaction each of the following represents:

(a) $\text{Ca}(s)+{\text{Br}}_2(l)⟶{\text{CaBr}}_2(s)$

(b) $\text{Ca}{\text{(OH)}}_2(aq)+2\text{HBr}(aq)⟶{\text{CaBr}}_2(aq)+2{\text{H}}_2\text{O}(l)$

(c) ${\text{C}}_6{\text{H}}_{12}(l)+9{\text{O}}_2(g)⟶6{\text{CO}}_2(g)+6{\text{H}}_2\text{O}(g)$

Indicate what type, or types, of reaction each of the following represents:

(a) ${\text{H}}_2\text{O}(g)+\text{C}(s)⟶\text{CO}(g)+{\text{H}}_2(g)$

(b) ${\text{2KClO}}_3(s)⟶2\text{KCl}(s)+3{\text{O}}_2(g)$

(c) $\text{Al}{\text{(OH)}}_3(aq)+3\text{HCl}(aq)⟶{\text{AlCl}}_3(aq)+3{\text{H}}_2\text{O}(l)$

(d) $\text{Pb}{({\text{NO}}_3)}_2(aq)+{\text{H}}_2{\text{SO}}_4(aq)⟶{\text{PbSO}}_4(s)+2{\text{HNO}}_3(aq)$

Silver can be separated from gold because silver dissolves in nitric acid while gold does not. Is the dissolution of silver in nitric acid an acid-base reaction or an oxidation-reduction reaction? Explain your answer.

Determine the oxidation states of the elements in the following compounds:

(a) NaI

(b) GdCl ₃

(c) LiNO ₃

(d) H ₂ Se

(e) Mg ₂ Si

(f) RbO ₂ , rubidium superoxide

(g) HF

Determine the oxidation states of the elements in the compounds listed. None of the oxygen-containing compounds are peroxides or superoxides.

(a) H ₃ PO ₄

(b) Al(OH) ₃

(c) SeO ₂

(d) KNO ₂

(e) In ₂ S ₃

(f) P ₄ O ₆

Determine the oxidation states of the elements in the compounds listed. None of the oxygen-containing compounds are peroxides or superoxides.

(a) H ₂ SO ₄

(b) Ca(OH) ₂

(c) BrOH

(d) ClNO ₂

(e) TiCl ₄

(f) NaH

Classify the following as acid-base reactions or oxidation-reduction reactions:

(a) ${\text{Na}}_2\text{S}(aq)+2\text{HCl}(aq)⟶2\text{NaCl}(aq)+{\text{H}}_2\text{S}(g)$

(b) $2\text{Na}(s)+2\text{HCl}(aq)⟶2\text{NaCl}(aq)+{\text{H}}_2(g)$

(c) $\text{Mg}(s)+{\text{Cl}}_2(g)⟶{\text{MgCl}}_2(s)$

(d) $\text{MgO}(s)+2\text{HCl}(aq)⟶{\text{MgCl}}_2(aq)+{\text{H}}_2\text{O}(l)$

(e) ${\text{K}}_3\text{P}(s)+2{\text{O}}_2(g)⟶{\text{K}}_3{\text{PO}}_4(s)$

(f) $3\text{KOH}(aq)+{\text{H}}_3{\text{PO}}_4(aq)⟶{\text{K}}_3{\text{PO}}_4(aq)+3{\text{H}}_2\text{O}(l)$