Chemical equation
C₃H₈ + O₂ → CO₂ + H₂O Balanced Equation
The C3H8 O2 balanced equation is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O. Propane burns in oxygen to form carbon dioxide and water, and the smallest whole-number coefficient ratio is 1 : 5 : 3 : 4.
Quick answer
Start with and balance carbon first, hydrogen second, and oxygen last.
| Coefficients | 1 : 5 : 3 : 4 |
|---|---|
| Reaction type | Complete combustion |
| Mole ratio | 1 : 5 : 3 : 4 |
Balanced Equation for C₃H₈ + O₂ → CO₂ + H₂O
The coefficient table shows why the balanced propane combustion equation uses the ratio 1 : 5 : 3 : 4.
Balanced equation
| Substance | Coefficient |
|---|---|
| C₃H₈ | 1 |
| O₂ | 5 |
| CO₂ | 3 |
| H₂O | 4 |
Read the balanced equation as: 1 molecule or mole of C₃H₈ reacts with 5 molecules or moles of O₂ to produce 3 molecules or moles of CO₂ and 4 molecules or moles of H₂O. In many homework answers, the same reaction may be written as C3H8 + 5O2 = 3CO2 + 4H2O.
How to Balance C₃H₈ + O₂ → CO₂ + H₂O
For hydrocarbon combustion equations, balance carbon first, hydrogen second, and oxygen last. Change coefficients only; do not change subscripts in C₃H₈, O₂, CO₂, or H₂O.
Step 1
Start with the unbalanced equation
C₃H₈ + O₂ → CO₂ + H₂O
Step 2
Balance carbon
C₃H₈ has 3 carbon atoms, so put 3 before CO₂: C₃H₈ + O₂ → 3CO₂ + H₂O.
Step 3
Balance hydrogen
C₃H₈ has 8 hydrogen atoms. Each H₂O has 2 hydrogen atoms, so put 4 before H₂O: C₃H₈ + O₂ → 3CO₂ + 4H₂O.
Step 4
Balance oxygen
The products now contain 6 O atoms in 3CO₂ and 4 O atoms in 4H₂O, for 10 O atoms total. Since O₂ has 2 O atoms, put 5 before O₂.
After carbon, hydrogen, and oxygen are balanced, the final C3H8 + O2 = CO2 + H2O balanced equation answer is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.
Atom Conservation Check
A balanced equation must have the same number of carbon, hydrogen, and oxygen atoms before and after the arrow.
| Element | Reactants | Products | Balanced |
|---|---|---|---|
| C | 3 | 3 | ✓ |
| H | 8 | 8 | ✓ |
| O | 10 | 10 | ✓ |
On the reactant side, 1C₃H₈ gives 3 carbon atoms and 8 hydrogen atoms, while 5O₂ gives 10 oxygen atoms. On the product side, 3CO₂ gives 3 carbon atoms and 6 oxygen atoms, and 4H₂O gives 8 hydrogen atoms and 4 oxygen atoms. The totals match.
Propane Combustion Equation
C₃H₈ is propane, so this reaction is commonly described as the propane combustion equation.
| Word equation | Propane + oxygen → carbon dioxide + water |
|---|---|
| Chemical equation | C₃H₈ + 5O₂ → 3CO₂ + 4H₂O |
| Fuel | Propane (C₃H₈) |
The words propane combustion equation and the chemical equation C3H8 + O2 → CO2 + H2O describe the same complete-combustion reaction. The unbalanced equation identifies the reactants and products; the balanced equation shows the correct proportions.
The balanced form is the one to use for mole ratios, limiting reactant calculations, theoretical yield, and atom-count checks.
What Type of Reaction Is C₃H₈ + O₂ → CO₂ + H₂O?
This is a complete combustion reaction because a hydrocarbon reacts with oxygen to produce carbon dioxide and water.
Reaction type
Complete combustion. Propane burns in enough oxygen and forms CO₂ and H₂O as the products.
General pattern
Hydrocarbon + O₂ → CO₂ + H₂O. Propane, C₃H₈, follows this combustion pattern.
Complete vs. incomplete combustion
With limited oxygen, propane can burn incompletely and form CO and/or carbon. The equation on this page is the complete combustion reaction, where the products are CO₂ and H₂O.
C₃H₈ + O₂ → CO₂ + H₂O Mole Ratio
Balanced coefficients become the mole ratio used in stoichiometry.
Mole ratio
C₃H₈ : O₂ : CO₂ : H₂O = 1 : 5 : 3 : 4
One mole of C₃H₈ reacts with five moles of O₂ to produce three moles of CO₂ and four moles of H₂O. A quick stoichiometry example is therefore:
1 mol C₃H₈ + 5 mol O₂ → 3 mol CO₂ + 4 mol H₂O
2 mol C₃H₈ needs 10 mol O₂ and forms 6 mol CO₂ plus 8 mol H₂O.
Calculate grams, moles, or product amounts for propane combustion in the stoichiometry calculator.
Reactants and Products
Identify each formula before using the equation in a mole-ratio, limiting-reactant, or theoretical-yield calculation.
| Side | Formula | Name | Role |
|---|---|---|---|
| Reactant | Propane | Fuel | |
| Reactant | Oxygen | Oxidizer | |
| Product | Carbon dioxide | Combustion product | |
| Product | Water | Combustion product |
For product details, see the molar mass pages for CO₂ or H₂O, or compare their Lewis structures on the CO₂ and H₂O structure pages.
Use This Equation in Chemistry Calculators
Once the equation is balanced, you can use it to work with specific amounts of C₃H₈, O₂, CO₂, or H₂O.
If propane and oxygen are not supplied in a 1 : 5 mole ratio, one reactant will limit the amount of CO₂ and H₂O that can form. You can also calculate the maximum theoretical yield of carbon dioxide or water from a known amount of propane.
- Use in Stoichiometry CalculatorConvert between C₃H₈, O₂, CO₂, and H₂O using the 1 : 5 : 3 : 4 mole ratio.
- Find Limiting ReactantCheck whether propane or oxygen runs out first for your amounts.
- Calculate Theoretical YieldEstimate the maximum CO₂ that can form from a known amount of propane.
- Balance Another Chemical EquationUse the equation balancer for any other combustion or homework reaction.
Related Chemical Equations
Compare propane combustion with similar combustion equations and other common balanced equations.
Frequently Asked Questions
What is the balanced equation for C3H8 + O2 → CO2 + H2O?
The balanced equation is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O. The smallest whole-number coefficients are 1 for C₃H₈, 5 for O₂, 3 for CO₂, and 4 for H₂O.
What are the coefficients for C3H8 + O2 → CO2 + H2O?
The coefficients are 1 : 5 : 3 : 4. That means C₃H₈ + 5O₂ → 3CO₂ + 4H₂O, with an implied coefficient of 1 before C₃H₈.
How do you balance C3H8 + O2 → CO2 + H2O?
Balance carbon first by placing 3 before CO₂. Balance hydrogen next by placing 4 before H₂O. The products then contain 10 oxygen atoms, so place 5 before O₂ to get C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.
What type of reaction is C3H8 + O2 → CO2 + H2O?
C₃H₈ + O₂ → CO₂ + H₂O is a complete combustion reaction. Propane is a hydrocarbon, and in enough oxygen it burns to form carbon dioxide and water.
What is the mole ratio of C3H8 to O2?
The mole ratio of C₃H₈ to O₂ is 1 : 5. One mole of propane needs five moles of oxygen for complete combustion.
What is the propane combustion equation?
The word equation is propane + oxygen → carbon dioxide + water. The balanced chemical equation is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.
Is this complete or incomplete combustion of propane?
This page shows complete combustion of propane because the products are CO₂ and H₂O. With limited oxygen, incomplete combustion can produce CO and/or carbon, but that is a different combustion equation.