Question

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Explanation:

Step1: Balance C atoms

Left has 1 C ($\text{CH}_4$), set $\text{CO}_2$ coefficient to 1.

$$\text{CH}_4 + \_\_\text{O}_2 ightarrow 1\text{CO}_2 + \_\_\text{H}_2\text{O}$$

Step2: Balance H atoms

Left has 4 H ($\text{CH}_4$), set $\text{H}_2\text{O}$ coefficient to 2.

$$\text{CH}_4 + \_\_\text{O}_2 ightarrow \text{CO}_2 + 2\text{H}_2\text{O}$$

Step3: Balance O atoms

Right has $2 + 2=4$ O, set $\text{O}_2$ coefficient to 2.

$$\text{CH}_4 + 2\text{O}_2 ightarrow \text{CO}_2 + 2\text{H}_2\text{O}$$

Step4: Verify all atoms

C: 1=1; H:4=4; O:4=4. Balanced.

Answer:

$$1\text{CH}_4 + 2\text{O}_2 ightarrow 1\text{CO}_2 + 2\text{H}_2\text{O}$$

(The coefficients in order are: 1, 2, 1, 2)