Carbon monoxide combines with oxygen to form carbon dioxide according to the equation:
`2CO(g) + O_(2)(g) to 2CO_(2)(g)` .
`200 cm^(3)` of carbon monoxide is mixed with `200 cm^(3)` of oxygen at room temperature and ignited.
What other gas, if any, may also be present ?

Explanation

To solve the problem, we need to analyze the reaction between carbon monoxide (CO) and oxygen (O₂) to form carbon dioxide (CO₂) based on the provided chemical equation:

**Step 1:** Write down the balanced chemical equation.
- The balanced equation is:
\[ 2CO(g) + O_2(g) \rightarrow 2CO_2(g) \]

**Step 2:** Determine the stoichiometric ratios from the equation.
- From the equation, we see that 2 moles of CO react with 1 mole of O₂ to produce 2 moles of CO₂. This means:
- 2 volumes of CO react with 1 volume of O₂.

**Step 3:** Convert the volumes of gases to moles using the stoichiometric ratios.
- Given that we have 200 cm³ of CO and 200 cm³ of O₂:
- According to the stoichiometry, 200 cm³ of CO would require:
\[ \text{Required O}_2 = \frac{200 \, \text{cm}^3 \, \text{CO}}{2} = 100 \, \text{cm}^3 \, \text{O}_2 \]

**Step 4:** Determine how much O₂ is left after the reaction.
- Since we started with 200 cm³ of O₂ and only 100 cm³ is required to react with the 200 cm³ of CO, the remaining O₂ will be:
\[ \text{Remaining O}_2 = 200 \, \text{cm}^3 - 100 \, \text{cm}^3 = 100 \, \text{cm}^3 \]

**Step 5:** Identify the products of the reaction.
- The reaction produces 200 cm³ of CO₂ from the complete reaction of 200 cm³ of CO with 100 cm³ of O₂.

**Final Answer:**
- Therefore, after the reaction, the gases present will be:
- 200 cm³ of CO₂ (produced)
- 100 cm³ of O₂ (remaining)

**Conclusion:**
The other gas that may also be present is oxygen (O₂), and the amount will be 100 cm³.

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