49 Balancing Chemical Equations Worksheets [with Answers] - Free Printable

Let’s go through each reaction one by one and figure out what type it is.

We’re looking for:
- Synthesis → Two or more things combine to make one product (A + B → AB)
- Decomposition → One thing breaks into two or more parts (AB → A + B)
- Combustion → Something burns with oxygen, usually making CO₂ and H₂O
- Single displacement → One element kicks another out of a compound (A + BC → AC + B)
- Double displacement → Two compounds swap partners (AB + CD → AD + CB)
- Acid-base → Acid + base → salt + water (often looks like double displacement but involves H⁺ and OH⁻)

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1) Na₃PO₄ + 3 KOH → 3 NaOH + K₃PO₄
→ Sodium phosphate and potassium hydroxide swap ions → Double displacement

2) MgCl₂ + Li₂CO₃ → MgCO₃ + 2 LiCl
→ Magnesium and lithium swap places → Double displacement

3) C₆H₁₂ + 9 O₂ → 6 CO₂ + 6 H₂O
→ Hydrocarbon + oxygen → carbon dioxide + water → Combustion

4) Pb + FeSO₄ → PbSO₄ + Fe
→ Lead kicks iron out of its compound → Single displacement

5) CaCO₃ → CaO + CO₂
→ One compound breaks into two → Decomposition

6) P₄ + 3 O₂ → 2 P₂O₃
→ Phosphorus and oxygen combine → Synthesis

7) 2 RbNO₃ + BeF₂ → Be(NO₃)₂ + 2 RbF
→ Rubidium and beryllium swap partners → Double displacement

8) 2 AgNO₃ + Cu → Cu(NO₃)₂ + 2 Ag
→ Copper kicks silver out → Single displacement

9) C₃H₆O + 4 O₂ → 3 CO₂ + 3 H₂O
→ Organic compound + oxygen → CO₂ + H₂O → Combustion

10) 2 C₅H₅ + Fe → Fe(C₅H₅)₂
→ Two cyclopentadienyl groups + iron → one compound → Synthesis

11) SeCl₆ + O₂ → SeO₂ + 3 Cl₂
→ Selenium hexachloride reacts with oxygen → selenium dioxide + chlorine gas
→ This is tricky — not classic combustion, not displacement. Actually, this is a redox reaction where oxygen replaces chlorine. But since it’s not fitting neatly, let’s see: it’s not synthesis, decomposition, single/double displacement, or acid-base. It might be considered a type of displacement (oxygen displacing chlorine), but technically, it’s often classified as combustion if it involves burning in oxygen — though here it’s not a hydrocarbon. Alternatively, some might call it “other” or “redox.” But based on common worksheet patterns, this is likely meant to be combustion because O₂ is a reactant and products are oxides and elements. Wait — actually, no: combustion typically produces CO₂ and H₂O from hydrocarbons. This is more like a single displacement if we think of O₂ displacing Cl₂? Not really. Let’s reconsider: SeCl₆ + O₂ → SeO₂ + 3Cl₂ — oxygen is taking the place of chlorine? Not exactly. Actually, this is a decomposition triggered by oxygen? No. Best fit: Combustion is wrong. Maybe single displacement? Not standard. Actually, this is a redox reaction, but since that’s not an option, and given the choices, perhaps it’s intended as combustion because O₂ is involved and it’s exothermic? Hmm. Looking at similar worksheets, reactions like this are sometimes called combustion even if not hydrocarbon-based. But let’s check: another way — it’s not synthesis, not decomposition, not double displacement, not acid-base. Single displacement? A + BC → AC + B — here, O₂ is not a single element replacing something. Actually, this is not single displacement. Perhaps it’s other, but since we must choose, and O₂ is a reactant producing oxides, I’ll go with combustion — though it’s a stretch. Wait — let me look again: SeCl₆ + O₂ → SeO₂ + 3Cl₂ — this is actually a disproportionation or redox, but for school level, they might expect combustion. Alternatively, maybe single displacement if we consider O₂ displacing Cl₂? Not accurate. I think the best answer here is combustion because it involves reaction with oxygen to form oxides. But let’s note: some sources might classify this differently. For now, I’ll say combustion.

Actually, wait — let’s think differently. In many curricula, combustion is specifically for hydrocarbons or organic compounds burning. This is inorganic. So perhaps it’s single displacement? No. Another idea: it could be seen as decomposition of SeCl₆ with O₂ helping? Not really. I recall that reactions like 2Mg + CO₂ → 2MgO + C are called combustion too. So yes, reaction with oxygen to produce oxides can be combustion. So I’ll stick with combustion.

But let’s double-check online or standard classification — actually, upon second thought, this reaction is not typical combustion. It’s more of a redox reaction, but since that’s not an option, and given the list, perhaps it’s single displacement? No. Let’s look at the products: SeO₂ and Cl₂ — oxygen has replaced chlorine in a way. Actually, this is similar to: 2FeCl₃ + 3H₂ → 2Fe + 6HCl — which is single displacement. Here, O₂ is acting like a displacing agent? Not really. I think the safest bet is to call it combustion because O₂ is a reactant and it’s producing oxides. Many worksheets accept that.

Alternatively, maybe it’s decomposition? No, because there are two reactants. I think I made a mistake earlier. Let me reclassify:

Actually, this reaction: SeCl₆ + O₂ → SeO₂ + 3Cl₂ — this is not standard. But in some contexts, it’s called a displacement reaction where oxygen displaces chlorine. Since oxygen is diatomic, it’s not single displacement. Perhaps it’s double displacement? No. I think for the purpose of this worksheet, since it’s not fitting perfectly, and O₂ is involved, they might expect combustion. But let’s see number 13 and 14 — they are decomposition. So perhaps 11 is also decomposition? No, two reactants. I found a better way: in some systems, this is classified as oxidation-reduction, but again, not an option. Given the choices, I’ll go with combustion as the closest.

Wait — let’s count the types used so far. We have double displacement, combustion, single displacement, decomposition, synthesis. For 11, if I say combustion, it’s okay. But let’s move on and come back.

12) 2 MgI₂ + Mn(SO₃)₂ → 2 MgSO₃ + MnI₄
→ Magnesium and manganese swap partners → Double displacement

13) O₃ → O· + O₂
→ Ozone breaks into oxygen atom and oxygen molecule → Decomposition

14) 2 NO₂ → 2 O₂ + N₂
→ Nitrogen dioxide breaks into oxygen and nitrogen → Decomposition

Now back to 11: SeCl₆ + O₂ → SeO₂ + 3Cl₂
After research in my mind, I recall that reactions where a compound reacts with oxygen to form oxides and other products are sometimes called combustion, even if not hydrocarbon. For example, 2CuS + 3O₂ → 2CuO + 2SO₂ is called combustion. So yes, this should be combustion.

But let’s confirm with logic: combustion is rapid oxidation, often with flame, producing heat and light. This reaction likely does that. So I’ll keep it as combustion.

However, I just realized: in some worksheets, they might expect single displacement for 11, but that doesn’t fit. Another thought: is it possible that O₂ is displacing Cl₂? In a way, yes — oxygen is taking the place of chlorine in the compound. So it could be seen as single displacement: A + BC → AC + B, where A is O₂, BC is SeCl₆, AC is SeO₂, B is Cl₂. But O₂ is not a single atom; it’s diatomic. Still, in broad terms, it might be accepted. But I think combustion is better.

Actually, let’s look at the answer key style. For consistency, I’ll assign:

11) Combustion

But I have a doubt. Let me think of another approach: the reaction SeCl₆ + O₂ → SeO₂ + 3Cl₂ can be viewed as oxygen oxidizing selenium and reducing itself? Not helpful. I found that in some educational resources, such reactions are classified as combustion when oxygen is a reactant and oxides are formed. So I’ll go with that.

Final list:

1) Double displacement
2) Double displacement
3) Combustion
4) Single displacement
5) Decomposition
6) Synthesis
7) Double displacement
8) Single displacement
9) Combustion
10) Synthesis
11) Combustion [though debatable, but fits best]
12) Double displacement
13) Decomposition
14) Decomposition

Wait, for 11, let me check online quickly in my mind — actually, I recall that the reaction of selenium tetrachloride with oxygen is not common, but for school purposes, since O₂ is a reactant and it's producing SeO₂, it's likely intended as combustion. Alternatively, some might say it's a redox reaction, but since that's not an option, combustion is the closest.

Another idea: perhaps it's single displacement if we consider O₂ as displacing Cl₂. But single displacement is typically element + compound → new element + new compound. Here, O₂ is an element (diatomic), SeCl₆ is compound, products are SeO₂ (compound) and Cl₂ (element). So yes! It fits: A + BC → AC + B, where A = O₂, B = Cl₂, C = Se (but Se is part of BC). More precisely: O₂ + SeCl₆ → SeO₂ + 3Cl₂ — so oxygen is displacing chlorine from selenium. So it is single displacement.

Yes! That makes sense. In single displacement, a more reactive element displaces a less reactive one from its compound. Here, oxygen is displacing chlorine. Although oxygen is usually not thought of as displacing halogens, in this case, it is. So I'll change 11 to single displacement.

Confirming: single displacement is A + BC → AC + B. Here, A is O₂, BC is SeCl₆, AC is SeO₂, B is Cl₂. Perfect match.

So corrected:

11) Single displacement

Now all are covered.

Final answers:

1) Double displacement
2) Double displacement
3) Combustion
4) Single displacement
5) Decomposition
6) Synthesis
7) Double displacement
8) Single displacement
9) Combustion
10) Synthesis
11) Single displacement
12) Double displacement
13) Decomposition
14) Decomposition

I think that's accurate.

Final Answer:
1) Double displacement
2) Double displacement
3) Combustion
4) Single displacement
5) Decomposition
6) Synthesis
7) Double displacement
8) Single displacement
9) Combustion
10) Synthesis
11) Single displacement
12) Double displacement
13) Decomposition
14) Decomposition