Propane burns in a closed vessel: C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(g)…

Step 1. The rate of the reaction. $\dfrac{0.0650\ \text{mol L}^{-1}\ \text{s}^{-1}}{5} = 0.0130\ \text{mol L}^{-1}\ \text{s}^{-1}$.

Step 2. Carbon dioxide. The coefficient is 3, so it forms at $3 \times 0.0130\ \text{mol L}^{-1}\ \text{s}^{-1} = 0.0390\ \text{mol L}^{-1}\ \text{s}^{-1}$.

Step 3. Water. The coefficient is 4, so it forms at $4 \times 0.0130\ \text{mol L}^{-1}\ \text{s}^{-1} = 0.0520\ \text{mol L}^{-1}\ \text{s}^{-1}$.