Question

5 zinc reacts with copper(ii) chloride to give copper metal and a solution of zinc (ii) chloride
_____ ( ) + ____ ( ) → ___ ( ) + ______ ( )
6 mixing solutions of calcium chloride and sodium carbonate will lead to the formation of calcium carbonate and sodium chloride. (carbonate is a polyatomic ion found on the back of your periodic table)
_____ ( ) + ____ ( ) → ___ ( ) + ______ ( )

Explanation:

Step1: Write unbalanced eq. (Q5)

$\text{Zn} + \text{CuCl}_2
ightarrow \text{Cu} + \text{ZnCl}_2$

Step2: Balance atoms (Q5)

All atoms are balanced; no changes needed.

Step3: Add states (Q5)

$\text{Zn (s)} + \text{CuCl}_2 \text{ (aq)}
ightarrow \text{Cu (s)} + \text{ZnCl}_2 \text{ (aq)}$

Step4: Write unbalanced eq. (Q6)

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

Step5: Balance Na/Cl atoms (Q6)

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

Step6: Add states (Q6)

$\text{CaCl}_2 \text{ (aq)} + \text{Na}_2\text{CO}_3 \text{ (aq)}
ightarrow \text{CaCO}_3 \text{ (s)} + 2\text{NaCl} \text{ (aq)}$

Answer:

Question 5:

$\boldsymbol{\text{Zn (s)}} + \boldsymbol{\text{CuCl}_2 \text{ (aq)}}
ightarrow \boldsymbol{\text{Cu (s)}} + \boldsymbol{\text{ZnCl}_2 \text{ (aq)}}$

Question 6:

$\boldsymbol{\text{CaCl}_2 \text{ (aq)}} + \boldsymbol{\text{Na}_2\text{CO}_3 \text{ (aq)}}
ightarrow \boldsymbol{\text{CaCO}_3 \text{ (s)}} + \boldsymbol{2\text{NaCl} \text{ (aq)}}$