Question

procedure: complete and balance the equations below. to help supply the missing reactants or products use both the reaction type guidelines and the completed equations given as models. remember the seven diatomic elements.
i. combination reactions
a. non - metals react with oxygen to produce non - metal oxides.

1. s₈(s) + ________ → so₂(g)
2. p₄(s) + ________ → p₄o₁₀(s)
3. ____ + ____ → co₂(g)

b. non - metal oxides react with water to produce acids

1. so₂(g) + h₂o(ℓ) → h₂so₃(aq) (sulfurous acid)
2. so₃(g) + h₂o(ℓ) → h₂so₄(aq) (sulfuric acid)
3. p₄o₁₀(s) + h₂o(ℓ) → h₃po₄(aq) (phosphoric acid)
4. co₂(g) + h₂o(ℓ) → h₂co₃ (carbonic acid)

c. metals react with oxygen to produce metal oxides.

1. ____ + ____ → li₂o(s)
2. ____ + ____ → mgo(s)
3. ____ + ____ → cao(s)
4. ____ + ____ → bao₂(s)

d. soluble metal oxides react with water to form hydroxides which dissociate in solution

1. na₂o(s) + h₂o(ℓ) → naoh(aq) → na⁺(aq) + oh⁻(aq)
2. k₂o(s) + h₂o(ℓ) → koh → k⁺ + oh⁻
3. mgo(s) + h₂o(ℓ) → mg(oh)₂ → mg²⁺ + 2oh⁻
4. cao(s) + h₂o(ℓ) → ca(oh)₂ → ca²⁺ + 2oh⁻

Explanation:

Step1: Balance equation 1

Sulfur reacts with oxygen. The balanced equation for $S_8(s)$ reacting with oxygen to form $SO_2(g)$ is $S_8(s)+8O_2(g)
ightarrow8SO_2(g)$. So the missing reactant is $8O_2$.

Step2: Balance equation 2

Phosphorus reacts with oxygen. The balanced equation for $P_4(s)$ reacting with oxygen to form $P_4O_{10}(s)$ is $P_4(s) + 5O_2(g)
ightarrow P_4O_{10}(s)$. So the missing reactant is $5O_2$.

Step3: Balance equation 3

Carbon reacts with oxygen to form carbon - dioxide. The balanced equation is $C(s)+O_2(g)
ightarrow CO_2(g)$. So the missing reactants are $C(s)$ and $O_2(g)$.

Step4: Balance equation 5

Sulfur trioxide reacts with water to form sulfuric acid. The balanced equation is $SO_3(g)+H_2O(l)
ightarrow H_2SO_4(aq)$.

Step6: Balance equation 6

The balanced equation for $P_4O_{10}(s)$ reacting with water to form $H_3PO_4(aq)$ is $P_4O_{10}(s)+6H_2O(l)
ightarrow4H_3PO_4(aq)$.

Step7: Balance equation 7

The balanced equation for $CO_2(g)$ reacting with water to form carbonic acid is $CO_2(g)+H_2O(l)
ightarrow H_2CO_3(aq)$.

Step8: Balance equation 8

The balanced equation for lithium reacting with oxygen to form lithium oxide is $4Li(s)+O_2(g)
ightarrow2Li_2O(s)$. So the missing reactants are $4Li$ and $O_2$.

Step9: Balance equation 9

The balanced equation for magnesium reacting with oxygen to form magnesium oxide is $2Mg(s)+O_2(g)
ightarrow2MgO(s)$. So the missing reactants are $2Mg$ and $O_2$.

Step10: Balance equation 10

The balanced equation for calcium reacting with oxygen to form calcium oxide is $2Ca(s)+O_2(g)
ightarrow2CaO(s)$. So the missing reactants are $2Ca$ and $O_2$.

Step11: Balance equation 11

The balanced equation for barium reacting with oxygen to form barium peroxide is $Ba(s)+O_2(g)
ightarrow BaO_2(s)$. So the missing reactants are $Ba$ and $O_2$.

Step13: Balance equation 13

The balanced equation for potassium oxide reacting with water is $K_2O(s)+H_2O(l)
ightarrow2KOH(aq)
ightarrow2K^+(aq)+2OH^-(aq)$. So the missing products are $2KOH$, $2K^+$ and $2OH^-$.

Step14: Magnesium oxide is not very soluble in water, but if we consider the reaction conceptually, the equation $MgO(s)+H_2O(l)

ightleftharpoons Mg(OH)_2(s)$ (it is a very limited reaction). But if we assume dissociation as in the pattern, $Mg(OH)_2(s)
ightleftharpoons Mg^{2 + }(aq)+2OH^-(aq)$. But the more correct form for the first - step reaction is $MgO(s)+H_2O(l)
ightarrow Mg(OH)_2(s)$ (very slow and limited).

Step15: The balanced equation for calcium oxide reacting with water is $CaO(s)+H_2O(l)

ightarrow Ca(OH)_2(aq)
ightarrow Ca^{2+}(aq)+2OH^-(aq)$. So the missing products are $Ca(OH)_2$, $Ca^{2+}$ and $2OH^-$.

Answer:

1. $8O_2$
2. $5O_2$
3. $C(s), O_2(g)$
4. $H_2SO_4(aq)$
5. $P_4O_{10}(s)+6H_2O(l)

ightarrow4H_3PO_4(aq)$

1. $H_2CO_3(aq)$
2. $4Li, O_2$
3. $2Mg, O_2$
4. $2Ca, O_2$
5. $Ba, O_2$
6. $2KOH, 2K^+, 2OH^-$
7. $Mg(OH)_2(s)$ (or conceptually $Mg^{2+}, 2OH^-$ with limited dissociation)
8. $Ca(OH)_2, Ca^{2+}, 2OH^-$