Question

8.__ al + fe₂o₃ → al₂o₃ + __ fe
9.__ na + i₂ → __ nai
10.__ mg + o₂ → __ mgo
11.__ na₂co₃ + cacl₂ → caco₃ + __ nacl
12.__ agno₃ + zncl₂ → agcl + __ zn(no₃)₂
13.__ feso₄ + (nh₄)₂s → fes + __ (nh₄)₂so₄

1. __ mg + h₃po₄ → mg₃(po₄)₂ + __ h₂
2. __ cl₂ + ali₃ → alcl₃ + __ i₂

Explanation:

Step1: Balance Al and Fe atoms

$2\text{Al} + \text{Fe}_2\text{O}_3
ightarrow \text{Al}_2\text{O}_3 + 2\text{Fe}$

Step2: Balance Na and I atoms

$2\text{Na} + \text{I}_2
ightarrow 2\text{NaI}$

Step3: Balance Mg and O atoms

$2\text{Mg} + \text{O}_2
ightarrow 2\text{MgO}$

Step4: Balance Na and Cl atoms

$\text{Na}_2\text{CO}_3 + \text{CaCl}_2
ightarrow \text{CaCO}_3 + 2\text{NaCl}$

Step5: Balance Ag, Cl, and nitrate ions

$2\text{AgNO}_3 + \text{ZnCl}_2
ightarrow 2\text{AgCl} + \text{Zn(NO}_3\text{)}_2$

Step6: Verify all atoms are balanced

$\text{FeSO}_4 + (\text{NH}_4\text{)}_2\text{S}
ightarrow \text{FeS} + (\text{NH}_4\text{)}_2\text{SO}_4$

Step7: Balance Mg, P, and H atoms

$3\text{Mg} + 2\text{H}_3\text{PO}_4
ightarrow \text{Mg}_3(\text{PO}_4\text{)}_2 + 3\text{H}_2$

Step8: Balance Cl and I atoms

$3\text{Cl}_2 + 2\text{AlI}_3
ightarrow 2\text{AlCl}_3 + 3\text{I}_2$

Answer:

1. $2\text{Al} + 1\text{Fe}_2\text{O}_3

ightarrow 1\text{Al}_2\text{O}_3 + 2\text{Fe}$

1. $2\text{Na} + 1\text{I}_2

ightarrow 2\text{NaI}$

1. $2\text{Mg} + 1\text{O}_2

ightarrow 2\text{MgO}$

1. $1\text{Na}_2\text{CO}_3 + 1\text{CaCl}_2

ightarrow 1\text{CaCO}_3 + 2\text{NaCl}$

1. $2\text{AgNO}_3 + 1\text{ZnCl}_2

ightarrow 2\text{AgCl} + 1\text{Zn(NO}_3\text{)}_2$

1. $1\text{FeSO}_4 + 1(\text{NH}_4\text{)}_2\text{S}

ightarrow 1\text{FeS} + 1(\text{NH}_4\text{)}_2\text{SO}_4$

1. $3\text{Mg} + 2\text{H}_3\text{PO}_4

ightarrow 1\text{Mg}_3(\text{PO}_4\text{)}_2 + 3\text{H}_2$

1. $3\text{Cl}_2 + 2\text{AlI}_3

ightarrow 2\text{AlCl}_3 + 3\text{I}_2$