Thermal = Heat and decompose = the process of breaking of any molecule. In thermal decomposition reaction, when heat is applied on any chemical compound or molecule, it gets break down (decompose) into two or more (multiple) chemical substances. Mostly thermal decomposition reactions will be done at high temperature.
CuCO₃(s) → CuO(s) + CO₂(g)
Copper carbonate → copper oxide + carbon dioxide
When copper carbonate is heated it undergoes thermal decomposition to produce copper oxide with release of carbon dioxide.
MgCO₃(s) → MgO(s) + CO₂(g)
Magnesium carbonate → magnesium oxide + carbon dioxide
When magnesium carbonate gets heated it undergoes thermal decomposition reaction and produce magnesium oxide with the release of carbon dioxide.
2NaHCO3 (s) → Na2CO3(s) + H2O (l) + CO2 (g)
Sodium bicarbonate → sodium carbonate + water + carbon dioxide
When sodium bicarbonate gets heated it undergoes thermal decomposition reaction and produce sodium carbonate with water and release of carbon dioxide gas.
ZnCO3 → ZnO + CO2
Zinc carbonate → Zinc oxide + carbon dioxide
When zinc carbonate gets heated undergoes thermal decomposition to give zinc oxide and carbon dioxide.
2Pb(NO3)2 → 2PbO + O2 + 4NO2
Lead (ii) nitrate → Lead oxide + oxygen gas + nitrogen dioxide
When lead(ii) nitrate gets heated undergoes thermal decomposition to give lead oxide with the release of nitrogen dioxide and oxygen gas.
KClO3(s) → 2KCl(s) + 3O2(g)
Potassium chlorate → potassium chloride + oxygen
When potassium chlorate gets heated it undergoes thermal decomposition to give potassium chloride and oxygen.
2Fe(OH)3 → Fe2O3 + 3H2O
Ferric oxyhydroxide → ferric oxide + water
When iron(iii) oxide-hydroxide or ferric oxyhydroxide gets heated it undergoes thermal decomposition to give ferric oxide and water.
H2C2O4.2H2O → H2C2O4 + 2H2O
Hydrated oxalic acid →oxalic acid + water
When hydrated oxalic acid gets heated it undergoes thermal decomposition to give oxalic acid and water.
PbCO3(s) → PbO(s) + CO2(g)
Lead carbonate → lead(ii) oxide + carbon dioxide
When lead carbonate gets heated it undergoes thermal decomposition to produce lead(ii) oxide and carbon dioxide.
2NaN3(s) → 2Na(s) + 3N2(g)
Sodium azide → sodium metal + nitrogen gas
When sodium azide gets heated it undergoes thermal decomposition to give sodium metal and nitrogen gas.
Cu(OH)2(s) → CuO(s) + H2O(l)
Copper hydroxide → copper(ii) oxide + water
When copper hydroxide gets heated it undergoes thermal decomposition to give copper(ii) dioxide and water.
CuSO4(s) → CuO(s) + SO3(g)
Copper sulphate → copper(ii) oxide + sulphur trioxide
When copper sulphate gets heated it undergoes thermal decomposition to give copper oxide with release of acidic sulphur trioxide gas.
2HgO(s) → 2Hg(l) + O2(g)
Mercuric oxide → mercury + oxygen
When mercuric oxide gets heated it undergoes thermal decomposition and produce mercury metal and oxygen gas.
2NaNO3(s) → 2NaNO2(s) + O2(g)
Sodium nitrate → sodium nitrite + oxygen
When sodium nitrate gets heated it undergoes thermal decomposition to giv sodium nitrite and release of oxygen gas.
2FeSO4(s) → Fe2O3(s) + SO2(g) + SO3(g)
Ferrous sulphate → ferric oxide + sulphur dioxide + sulphur trioxide
When ferrous sulphate gets heated it undergoes thermal decomposition to produce ferric oxide with the release of sulphur dioxide and sulphur trioxide gas.
H2O2(l) → 2H2O(l) + O2(g)
Hydrogen peroxide → water + oxygen gas
When hydrogen gets heated it undergoes thermal decomposition to give water with release of oxygen gas.
NH4Cl → NH3 + HCl
Ammonium chloride → ammonia gas + hydrochloric acid
When ammonium chloride gets heated it undergoes thermal decomposition to give ammonia gas and hydrochloric acid.
C12H22O11 → 12C + 11H2O
Sucrose → carbon + water
When sucrose gets heated it undergoes thermal decomposition and produce carbon with water.
NaNO3(s) → NaNO3(l)
Sodium nitrate (solid) → sodium nitrate (liquid)
When sodium nitrate in solid form gets heated it undergoes thermal decomposition and changes to liquid form of sodium nitrate.
(NH4)2Cr2O7 → Cr2O3 + 4H2O + N2
Ammonium dichromate → chromium oxide + water + nitrogen gas
When ammonium dichromate gets heated it undergoes thermal decomposition to give chromium oxide with water and release of nitrogen gas.
H2CO3 → CO2 + H2O
Carbonic acid → carbon dioxide + water
When carbonic acid gets heated it undergoes thermal decomposition to produce carbon dioxide gas and water.
Mg(OH)2 → MgO + H2O
Magnesium hydroxide → magnesium oxide + water
When magnesium hydroxide gets heated it undergoes thermal decomposition to give magnesium oxide and water.
2Ag2O → 4Ag + O2
Silver oxide → silver metal + oxygen
When silver oxide gets heated it undergoes thermal decomposition to give silver metal and oxygen.
C4H10 → C3H6 + CH4
Butane → propane + methane
When butane gets heated it undergoes thermal decomposition to give propane and methane.
Detailed explanation of thermal decomposition reaction
Thermal decomposition reactions are those reaction in which the chemical compound when heated on high temperature gets broken down in more than two chemical substances. So, in thermal decomposition reaction high amount of heat energy gets absorbed by the reactants before it getting break down into products. The resulting formed substances i.e. the products could be the compounds or an atom or elements.
The thermal decomposition reaction example comes under endothermic reaction as the heat is absorbed in this reaction. The most common example for thermal decomposition reaction is of metal carbonates. Many metal carbonates get decomposes after heating and produce metal oxide and carbon dioxide. In this reaction many chemical compounds get decomposed itself like carbonates without reacting with other chemical substances or addition of any catalyst.
All metal carbonates do not show thermal decomposition, compounds like lead, zinc and copper carbonate undergoes thermal decomposition reaction. But other carbonates like potassium carbonate does not easily decompose thermally unless applying high temperature heat. In this reaction there only one reactant and two or more products are there.
Conclusion
- In thermal decomposition reaction heat energy is required.
- This reaction is done at high temperature.
- In this reaction there is one reactant and two products are present.
- This reaction occur itself without addition of any other chemical or catalyst.
- There is a colour change in this reaction from reactant to product.
- But all compounds do not show colour change.
- This reaction generally occurs in carbonates unless in some carbonates like potassium carbonate.
Hello everyone, I am Dr. Shruti M Ramteke, I did my Ph.D. in chemistry. I am passionate about writing and like to share my knowledge with others . Feel free to contact me on linkedin
Hi Fellow Reader,
We're a small team at Techiescience, working hard among the big players. If you like what you see, please share our content on social media. Your support makes a big difference. Thank you!