How many moles of CO$_2$ are produced when ethanol is burnt with 6g of oxygen

To solve this problem, we need to follow the stoichiometry of the combustion reaction of ethanol.

1. Analyze the Question

We are given the mass of oxygen ($O_2$) used to burn ethanol ($C_2H_5OH$) and asked to find the number of moles of carbon dioxide ($CO_2$) produced.

2. Explain the Concept

First, we must write the balanced chemical equation for the complete combustion of ethanol:

From the balanced equation:

• 3 moles of $O_2$ produce 2 moles of $CO_2$.

3. Show the Solution

Step 1: Calculate the molar mass of $O_2$. The atomic mass of Oxygen (O) = 16.0 g/mol. Molar mass of $O_2 = 16.0 \times 2 = 32.0 \text{ g/mol}$.

Step 2: Calculate the number of moles of $O_2$ provided.

Step 3: Use the mole ratio to find the moles of $CO_2$. From the balanced equation, the ratio of $O_2$ to $CO_2$ is $3:2$.

4. Identify the Answer

Comparing our result to the options provided, the correct value is 0.125.

125.

5. Exam Tip

Always ensure your chemical equation is balanced before performing stoichiometric calculations. A common mistake is to use the wrong mole ratio (e.g., using $1:1$ instead of $3:2$). If you are ever unsure about the coefficients, quickly re-check the number of atoms on both sides of the arrow!