100cm 3 of oxygen and 10cm 3 of butane measured at room temperature and pressure

Explanation

To answer this question, we need to first understand the balanced chemical equation of the reaction between butane and oxygen. Butane (C₄H₁₀) reacts with oxygen (O₂) to form carbon dioxide (CO₂) and water (H₂O).

The balanced chemical equation for this reaction is:

2C₄H₁₀ + 13O₂ ? 8CO₂ + 10H₂O

From the balanced equation, we can see that 2 moles of butane react with 13 moles of oxygen. To determine the volume of the mixture, we need to find the volume of the unreacted oxygen after the reaction.

We have 10 cm³ of butane, and since the ratio of butane to oxygen is 2:13, we can calculate that 10 cm³ of butane will react with 65 cm³ of oxygen.

Since we initially had 100 cm³ of oxygen, the remaining unreacted oxygen is:

100 cm³ - 65 cm³ = 35 cm³

Now, let's find the volume of the products of the reaction. From the balanced equation, we can see that the reaction produces 8 moles of CO₂ and 10 moles of H₂O for every 2 moles of butane. Since we have 10 cm³ of butane, the volume of CO₂ produced is:

\(\frac{8}{2}\) * 10 cm³ = 40 cm³

The volume of H₂O produced is:

\(\frac{10}{2}\) * 10 cm³ = 50 cm³

However, the water produced will condense at room temperature and pressure, so we only need to consider the volume of CO₂ and unreacted oxygen in the mixture.

Therefore, the total volume of the mixture when brought back to the original conditions of measurements is:

35 cm³ (unreacted oxygen) + 40 cm³ (CO₂) = 75 cm³

The correct option isOption C: 75 cm³.