How to Calculate the Final Centimolarity of a Solution?

Question:

If caffeine has a molecular weight of 194 g/mole, what would the final centimolarity of a solution be if you dissolve 0.05 kilograms of caffeine in 150 deciliters of water?

Answer:

To calculate the final centimolarity of the caffeine solution, we need to follow these steps:

Step 1: Calculate Number of Moles of Caffeine

Number of moles of caffeine = mass of caffeine / molecular weight of caffeine

Number of moles of caffeine = 0.05 kg / 194 g/mol = 0.257732 moles

Step 2: Calculate Total Volume of the Solution

Total volume of solution = 150 dL = 15000 mL

Step 3: Calculate Final Centimolarity

C = (number of moles of solute / total volume of solution) x 1000

C = (0.257732 moles / 15000 mL) x 1000 = 0.0172 M or 1.72 cmol/L

Therefore, the final centimolarity of the caffeine solution would be 1.72 cmol/L if you dissolve 0.05 kilograms of caffeine in 150 deciliters of water.