Types of Chemical Reactions Worksheets - Free Printable - Free Printable

Let’s go step by step through each reaction. We’ll predict the products based on the type of reaction, then balance the equation.

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Part A:

1) C (Combustion): C₃H₆O + O₂ → ?
Combustion means burning in oxygen → produces CO₂ and H₂O.
Unbalanced: C₃H₆O + O₂ → CO₂ + H₂O
Balance C: 3 CO₂
Balance H: 6 H atoms → 3 H₂O
Now count O: Left = 1 (from C₃H₆O) + 2x (from O₂). Right = 3×2 + 3×1 = 9
So: 1 + 2x = 9 → 2x = 8 → x = 4
✔ Balanced: C₃H₆O + 4O₂ → 3CO₂ + 3H₂O

2) DR (Double Replacement): CuCl₂ + H₂S → ?
Swap ions: Cu²⁺ with S²⁻ → CuS; H⁺ with Cl⁻ → HCl
Unbalanced: CuCl₂ + H₂S → CuS + HCl
Balance Cl and H: need 2 HCl
✔ Balanced: CuCl₂ + H₂S → CuS + 2HCl

3) D (Decomposition): ZnCO₃ → ?
Metal carbonates break into metal oxide + CO₂
✔ ZnCO₃ → ZnO + CO₂ (already balanced)

4) SR (Single Replacement): Na + MgCl₂ → ?
Na is more reactive than Mg? Wait — check activity series: Na is ABOVE Mg → so YES, Na can replace Mg.
But wait — actually, sodium is very reactive, but magnesium chloride is stable. In reality, sodium would react with water first, but here we assume dry conditions.
Actually, let’s think: Single replacement: Na replaces Mg? But Mg is less reactive than Na? No — wait, activity series: K > Na > Ca > Mg... So Na is MORE reactive than Mg → yes, it should displace.
Products: NaCl + Mg
Unbalanced: Na + MgCl₂ → NaCl + Mg
Balance: 2Na + MgCl₂ → 2NaCl + Mg
✔ 2Na + MgCl₂ → 2NaCl + Mg

Wait — correction: Actually, in standard chemistry, sodium does NOT typically displace magnesium from its salts because magnesium is quite stable and sodium reacts violently with moisture. But for textbook purposes, if we follow reactivity series strictly, Na is above Mg → so it should work. However, many textbooks say that alkali metals like Na don’t usually do single replacement with transition or alkaline earth metals in solid state — but since this is a worksheet, we’ll go with the rule.

Alternatively — maybe the problem expects no reaction? But it says “predict products”, so likely they want us to proceed.

Actually, let me double-check: Standard activity series: Li > K > Ba > Sr > Ca > Na > Mg > Al... So Na is ABOVE Mg → so Na can displace Mg. Yes.

So: 2Na + MgCl₂ → 2NaCl + Mg

5) S (Synthesis): K + Cl₂ → ?
Potassium + chlorine gas → potassium chloride
K is +1, Cl is -1 → KCl
Unbalanced: K + Cl₂ → KCl
Balance: 2K + Cl₂ → 2KCl
✔ 2K + Cl₂ → 2KCl

6) SR: Cu + AgNO₃ → ?
Copper is above silver in activity series → yes, displaces.
Cu + AgNO₃ → Cu(NO₃)₂ + Ag
Balance: Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
✔ Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

7) D: NO₂ → ?
Nitrogen dioxide decomposition? This is tricky. Usually, NO₂ doesn’t decompose easily, but sometimes it forms N₂O₄ (dimer), but that’s not decomposition. Or under heat: 2NO₂ → 2NO + O₂
Yes, that’s a known decomposition.
✔ 2NO₂ → 2NO + O₂

8) DR: CaO + Mg(NO₃)₂ → ?
Double replacement: Ca²⁺ with NO₃⁻ → Ca(NO₃)₂; Mg²⁺ with O²⁻ → MgO
But CaO is a base, Mg(NO₃)₂ is salt — might not react unless in solution. But assuming aqueous:
CaO + H₂O → Ca(OH)₂ first? But the problem doesn’t say. Let’s assume direct swap.
Products: Ca(NO₃)₂ + MgO
Check solubility: Ca(NO₃)₂ soluble, MgO insoluble? Actually MgO is slightly soluble, but often considered precipitate.
Equation: CaO + Mg(NO₃)₂ → Ca(NO₃)₂ + MgO
Already balanced? Atoms: Ca:1, O:1+6=7? Wait left: CaO has 1 O, Mg(NO₃)₂ has 6 O → total 7 O. Right: Ca(NO₃)₂ has 6 O, MgO has 1 → 7 O. Good.
✔ CaO + Mg(NO₃)₂ → Ca(NO₃)₂ + MgO

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Part B:

1) SR: Magnesium bromide + Chlorine → ?
Chlorine is more reactive than bromine → displaces Br from MgBr₂
MgBr₂ + Cl₂ → MgCl₂ + Br₂
Balance: MgBr₂ + Cl₂ → MgCl₂ + Br₂ (already balanced)
✔ MgBr₂ + Cl₂ → MgCl₂ + Br₂

2) DR: Silver nitrate + Zinc chloride → ?
AgNO₃ + ZnCl₂ → AgCl (precipitate) + Zn(NO₃)₂
Balance: 2AgNO₃ + ZnCl₂ → 2AgCl + Zn(NO₃)₂
✔ 2AgNO₃ + ZnCl₂ → 2AgCl + Zn(NO₃)₂

3) S: Aluminum + Oxygen → ?
Al + O₂ → Al₂O₃
Balance: 4Al + 3O₂ → 2Al₂O₃
✔ 4Al + 3O₂ → 2Al₂O₃

4) D: Magnesium hydroxide → ?
Heating metal hydroxides → metal oxide + water
Mg(OH)₂ → MgO + H₂O
Already balanced.
✔ Mg(OH)₂ → MgO + H₂O

5) S: Magnesium + Iodine → ?
Mg + I₂ → MgI₂
Balance: Mg + I₂ → MgI₂ (already balanced)
✔ Mg + I₂ → MgI₂

6) SR: Sodium + Water → ?
Very reactive! Sodium displaces hydrogen from water.
Na + H₂O → NaOH + H₂
Balance: 2Na + 2H₂O → 2NaOH + H₂
✔ 2Na + 2H₂O → 2NaOH + H₂

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Final Answer:

Part A:
1) C₃H₆O + 4O₂ → 3CO₂ + 3H₂O
2) CuCl₂ + H₂S → CuS + 2HCl
3) ZnCO₃ → ZnO + CO₂
4) 2Na + MgCl₂ → 2NaCl + Mg
5) 2K + Cl₂ → 2KCl
6) Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
7) 2NO₂ → 2NO + O₂
8) CaO + Mg(NO₃)₂ → Ca(NO₃)₂ + MgO

Part B:
1) MgBr₂ + Cl₂ → MgCl₂ + Br₂
2) 2AgNO₃ + ZnCl₂ → 2AgCl + Zn(NO₃)₂
3) 4Al + 3O₂ → 2Al₂O₃
4) Mg(OH)₂ → MgO + H₂O
5) Mg + I₂ → MgI₂
6) 2Na + 2H₂O → 2NaOH + H₂