Answer: 1)
![2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O](https://img.qammunity.org/2022/formulas/chemistry/high-school/h1v8pfr24imhdi8frtmzpuxrcfylixkren.png)
2)
![2C_4H_(10)+13O_2\rightarrow 8CO_2+10H_2O](https://img.qammunity.org/2022/formulas/chemistry/college/odhug3fcqltkapn19n5fh76xu1xt25khzc.png)
3)
![2C_8H_(18)+25O_2\rightarrow 16CO_2+18H_2O](https://img.qammunity.org/2022/formulas/chemistry/high-school/xs9xx5ikbjqnkktcdud5wg16cqcvvpfq5n.png)
4)
![2C_(10)H_(22)+31O_2\rightarrow 20CO_2+22H_2O](https://img.qammunity.org/2022/formulas/chemistry/high-school/h4spyfvhjzum8iteus3kx1xpznwbel2bc9.png)
Step-by-step explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side.
The balanced chemical reactions will be:
1) Ethane + Oxygen = Carbon Dioxide + Water :
![2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O](https://img.qammunity.org/2022/formulas/chemistry/high-school/h1v8pfr24imhdi8frtmzpuxrcfylixkren.png)
2) Butane + Oxygen = Carbon Dioxide + Water :
![2C_4H_(10)+13O_2\rightarrow 8CO_2+10H_2O](https://img.qammunity.org/2022/formulas/chemistry/college/odhug3fcqltkapn19n5fh76xu1xt25khzc.png)
3) Octane + Oxygen = Carbon Dioxide + water:
![2C_8H_(18)+25O_2\rightarrow 16CO_2+18H_2O](https://img.qammunity.org/2022/formulas/chemistry/high-school/xs9xx5ikbjqnkktcdud5wg16cqcvvpfq5n.png)
4) Decane + Oxygen = Carbon Dioxide + Water :
![2C_(10)H_(22)+31O_2\rightarrow 20CO_2+22H_2O](https://img.qammunity.org/2022/formulas/chemistry/high-school/h4spyfvhjzum8iteus3kx1xpznwbel2bc9.png)