Chapter 20, Problem 1TE

(a)

To determine

The balance chemical equations for the following unbalanced equation: $\_\text{Fe}\left(s\right)+\_{\text{O}}_2\left(g\right)\to \_{\text{Fe}}_2{\text{O}}_3\left(s\right)$

Answer to Problem 1TE

The balanced equation is $4\text{Fe}\left(s\right)+3{\text{O}}_2\left(g\right)\to 2{\text{Fe}}_2{\text{O}}_3\left(s\right)$ .

Explanation of Solution

In a given chemical equation, $\_\text{Fe}\left(s\right)+\_{\text{O}}_2\left(g\right)\to \_{\text{Fe}}_2{\text{O}}_3\left(s\right)$

There are two oxygen atoms in the reactant side and three oxygen atoms on the product side, so to balance the oxygen atoms the reactant side oxygen molecule is multiplied by three and the product side should be multiplied by two. Thus the equation will become,

$\_\text{Fe}\left(s\right)+3{\text{O}}_2\left(g\right)\to 2{\text{Fe}}_2{\text{O}}_3\left(s\right)$ .

Now, there is only one iron atom in the reactant side and four iron atoms in the product side, so to balance the iron atoms the iron atom on the reactant side should be multiplied by four. Thus the equation will now become,

$4\text{Fe}\left(s\right)+3{\text{O}}_2\left(g\right)\to 2{\text{Fe}}_2{\text{O}}_3\left(s\right)$ .

Conclusion:

Therefore, the balanced equation is $4\text{Fe}\left(s\right)+3{\text{O}}_2\left(g\right)\to 2{\text{Fe}}_2{\text{O}}_3\left(s\right)$ .

(b)

To determine

The balance chemical equation for the following unbalanced equation: $\_{\text{H}}_2\left(g\right)+\_{\text{N}}_2\left(g\right)\to \_{\text{NH}}_3\left(g\right)$

Answer to Problem 1TE

The balanced equation is $3{\text{H}}_2\left(g\right)+1{\text{N}}_2\left(g\right)\to 2{\text{NH}}_3\left(g\right)$ .

Explanation of Solution

In a given chemical equation,

$\_{\text{H}}_2\left(g\right)+\_{\text{N}}_2\left(g\right)\to \_{\text{NH}}_3\left(g\right)$

There are two nitrogen atoms in the reactant side and only one nitrogen atom on the product side, so to balance the nitrogen atoms the product side ammonia molecule should be multiplied by two. Thus the equation will become,

$\_{\text{H}}_2\left(g\right)+1{\text{N}}_2\left(g\right)\to 2{\text{NH}}_3\left(g\right)$ .

Now, there are two hydrogen atoms in the reactant side and three hydrogen atoms on the product side, so to balance the hydrogen atoms the reactant side hydrogen molecule should be multiplied by three. Thus the equation will become,

$3{\text{H}}_2\left(g\right)+1{\text{N}}_2\left(g\right)\to 2{\text{NH}}_3\left(g\right)$ .

Conclusion:

Therefore, the balanced equation is $3{\text{H}}_2\left(g\right)+1{\text{N}}_2\left(g\right)\to 2{\text{NH}}_3\left(g\right)$ .

(c)

To determine

The balance chemical equation for the following unbalanced equation: $\_{\text{Cl}}_2\left(g\right)+\_\text{KBr}\left(aq\right)\to \_{\text{Br}}_2\left(l\right)+\_\text{KCl}\left(aq\right)$

Answer to Problem 1TE

The balanced equation is $1{\text{Cl}}_2\left(g\right)+2\text{KBr}\left(aq\right)\to 1{\text{Br}}_2\left(l\right)+2\text{KCl}\left(aq\right)$ .

Explanation of Solution

In a given chemical equation,

$\_{\text{Cl}}_2\left(g\right)+\_\text{KBr}\left(aq\right)\to \_{\text{Br}}_2\left(l\right)+\_\text{KCl}\left(aq\right)$

There are two chlorine atoms in the reactant side and only one chlorine atom on the product side, so to balance the chlorine atoms the product side potassium chloride molecule should be multiplied by two. Thus the equation will become,

$1{\text{Cl}}_2\left(g\right)+\_\text{KBr}\left(aq\right)\to \_{\text{Br}}_2\left(l\right)+2\text{KCl}\left(aq\right)$ .

Now, there is only one bromine atom in the reactant side and two bromine atoms in the product side, so to balance the bromine atoms the bromine atom on the reactant side in potassium bromide molecule should be multiplied by two. Thus the equation will now become,

$1{\text{Cl}}_2\left(g\right)+2\text{KBr}\left(aq\right)\to 1{\text{Br}}_2\left(l\right)+2\text{KCl}\left(aq\right)$ .

Conclusion:

Therefore, the balanced equation is $1{\text{Cl}}_2\left(g\right)+2\text{KBr}\left(aq\right)\to 1{\text{Br}}_2\left(l\right)+2\text{KCl}\left(aq\right)$ .

(d)

To determine

The balance chemical equation for the following unbalanced equation: $\_{\text{CH}}_4\left(g\right)+\_{\text{O}}_2\left(g\right)\to \_{\text{CO}}_2\left(g\right)+\_{\text{H}}_2\text{O}\left(l\right)$

Answer to Problem 1TE

The balanced equation is $1{\text{CH}}_4\left(g\right)+2{\text{O}}_2\left(g\right)\to 1{\text{CO}}_2\left(g\right)+2{\text{H}}_2\text{O}\left(l\right)$ .

Explanation of Solution

In a given chemical equation,

$\_{\text{CH}}_4\left(g\right)+\_{\text{O}}_2\left(g\right)\to \_{\text{CO}}_2\left(g\right)+\_{\text{H}}_2\text{O}\left(l\right)$

There is one carbon atom on the reactant side and one carbon atom at the product side, thus carbon is balanced in the given reaction.There are two oxygen atoms in the reactant side and three oxygen atoms on the product side, so to balance the oxygen atoms the reactant side oxygen molecule is multiplied by two and the product side water molecule should be multiplied by two. Thus the equation will become,

$1{\text{CH}}_4\left(g\right)+2{\text{O}}_2\left(g\right)\to 1{\text{CO}}_2\left(g\right)+2{\text{H}}_2\text{O}\left(l\right)$ .

Now, there are four hydrogen atoms on the reactant side and four hydrogen atoms at the product side, thus hydrogen is also balanced in the given reaction.

Conclusion:

Therefore, the balanced equation is $1{\text{CH}}_4\left(g\right)+2{\text{O}}_2\left(g\right)\to 1{\text{CO}}_2\left(g\right)+2{\text{H}}_2\text{O}\left(l\right)$ .