Study the reaction scheme below in which compound Y is produced by the reaction of compound X with water - Leaving Cert Chemistry - Question 8 - 2021

To find the concentration in moles per litre, follow these steps:

1. Calculate the volume of isopropyl alcohol in 100 cm³: The sanitizer is 70% (v/v), hence:

   $70 \text{ cm}^3 \text{ CH}_3\text{CH(OH)CH}_3 \text{ per } 100 \text{ cm}^3$

2. Calculate the volume of isopropyl alcohol in 1 litre:

   $700 \text{ cm}^3 \text{ CH}_3\text{CH(OH)CH}_3 \text{ per litre}$

3. Calculate the mass of isopropyl alcohol: Using density (0.8 g/cm³):

   $700 \text{ cm}^3 \times 0.8 \text{ g/cm}^3 = 560 \text{ g CH}_3\text{CH(OH)CH}_3 \text{ per litre}$

4. Calculate the number of moles of isopropyl alcohol: The molar mass of isopropyl alcohol (C₃H₈O) is approximately 60.094 g/mol. Thus:

   $n = \frac{\text{mass}}{\text{molar mass}} = \frac{560 \text{ g}}{60.094 \text{ g/mol}} \approx 9.3 \text{ moles per litre}$

Thus, the concentration of isopropyl alcohol is approximately 9.33 moles per litre.