Question

1. balance each equation for a single replacement reaction.

(a) k + h₃po₄ → k₃po₄ + h₂
(b) fe + h₂s → fe₂s₃ + h₂
(c) cl₂ + mgbr₂ → mgcl₂ + br₂
(d) cu + ag₂co₃ → cuco₃ + ag
(e) br₂ + ki → i₂ + kbr
(f) mg + zn₃(po₄)₂ → mg₃(po₄)₂ + zn
(g) k + al(no₃)₃ → al + kno₃
(h) ca + h₂o → ca(oh)₂ + h₂
(i) na + h₂so₄ → na₂so₄ + h₂

Explanation:

Step1: Balance equation (a)

We need to balance the number of atoms on both sides. For the potassium ($K$), phosphorus ($P$), oxygen ($O$) and hydrogen ($H$) atoms.
$6K + 2H_3PO_4
ightarrow 2K_3PO_4+3H_2$

Step2: Balance equation (b)

Balance iron ($Fe$) and hydrogen ($H$) and sulfur ($S$) atoms.
$2Fe + 3H_2S
ightarrow Fe_2S_3 + 3H_2$

Step3: Balance equation (c)

Balance chlorine ($Cl$), magnesium ($Mg$) and bromine ($Br$) atoms.
$Cl_2+MgBr_2
ightarrow MgCl_2 + Br_2$

Step4: Balance equation (d)

Balance copper ($Cu$), silver ($Ag$) and carbon ($C$) and oxygen ($O$) atoms.
$Cu+Ag_2CO_3
ightarrow CuCO_3 + 2Ag$

Step5: Balance equation (e)

Balance bromine ($Br$), iodine ($I$) and potassium ($K$) atoms.
$Br_2 + 2KI
ightarrow I_2+2KBr$

Step6: Balance equation (f)

Balance magnesium ($Mg$), zinc ($Zn$), phosphorus ($P$) and oxygen ($O$) atoms.
$3Mg+Zn_3(PO_4)_2
ightarrow Mg_3(PO_4)_2 + 3Zn$

Step7: Balance equation (g)

Balance potassium ($K$), aluminum ($Al$), nitrogen ($N$) and oxygen ($O$) atoms.
$3K+Al(NO_3)_3
ightarrow Al + 3KNO_3$

Step8: Balance equation (h)

Balance calcium ($Ca$), hydrogen ($H$) and oxygen ($O$) atoms.
$Ca + 2H_2O
ightarrow Ca(OH)_2+H_2$

Step9: Balance equation (i)

Balance sodium ($Na$), hydrogen ($H$), sulfur ($S$) and oxygen ($O$) atoms.
$2Na + H_2SO_4
ightarrow Na_2SO_4+H_2$

Answer:

(a) $6K + 2H_3PO_4
ightarrow 2K_3PO_4+3H_2$
(b) $2Fe + 3H_2S
ightarrow Fe_2S_3 + 3H_2$
(c) $Cl_2+MgBr_2
ightarrow MgCl_2 + Br_2$
(d) $Cu+Ag_2CO_3
ightarrow CuCO_3 + 2Ag$
(e) $Br_2 + 2KI
ightarrow I_2+2KBr$
(f) $3Mg+Zn_3(PO_4)_2
ightarrow Mg_3(PO_4)_2 + 3Zn$
(g) $3K+Al(NO_3)_3
ightarrow Al + 3KNO_3$
(h) $Ca + 2H_2O
ightarrow Ca(OH)_2+H_2$
(i) $2Na + H_2SO_4
ightarrow Na_2SO_4+H_2$