Questions: The drawing below shows a mixture of molecules: carbon nitrogen hydrogen oxygen sulfur chlorine Suppose the following chemical reaction can take place in this mixture: 2 C2 H2(g) + 5 O2(g) -> 4 CO2(g) + 2 H2 O(g) Of which reactant are there the most initial moles? Enter its chemical formula: Of which reactant are there the least initial moles? Enter its chemical formula: Which reactant is the limiting reactant? Enter its chemical formula:

Solution Steps

The chemical reaction given is: \[ 2 \mathrm{C}_{2} \mathrm{H}_{2}(g) + 5 \mathrm{O}_{2}(g) \rightarrow 4 \mathrm{CO}_{2}(g) + 2 \mathrm{H}_{2} \mathrm{O}(g) \]

The reactants in this reaction are acetylene (\(\mathrm{C}_{2} \mathrm{H}_{2}\)) and oxygen (\(\mathrm{O}_{2}\)).

To determine which reactant has the most and least initial moles, we need the initial quantities of each reactant. Since the problem does not provide specific quantities, we assume hypothetical values or use a visual representation if available. For this example, let's assume:

• There are 3 moles of \(\mathrm{C}_{2} \mathrm{H}_{2}\).
• There are 8 moles of \(\mathrm{O}_{2}\).

• Most Initial Moles: Compare the moles of \(\mathrm{C}_{2} \mathrm{H}_{2}\) and \(\mathrm{O}_{2}\). Here, \(\mathrm{O}_{2}\) has more moles (8 moles).
• Least Initial Moles: \(\mathrm{C}_{2} \mathrm{H}_{2}\) has fewer moles (3 moles).

To find the limiting reactant, compare the mole ratio from the balanced equation to the initial moles:

• The reaction requires 2 moles of \(\mathrm{C}_{2} \mathrm{H}_{2}\) for every 5 moles of \(\mathrm{O}_{2}\).
• Calculate the required moles of \(\mathrm{O}_{2}\) for 3 moles of \(\mathrm{C}_{2} \mathrm{H}_{2}\): \[ \text{Required } \mathrm{O}_{2} = \left(\frac{5}{2}\right) \times 3 = 7.5 \text{ moles} \]
• Since there are 8 moles of \(\mathrm{O}_{2}\), \(\mathrm{C}_{2} \mathrm{H}_{2}\) is the limiting reactant because it will run out first.

Final Answer