Final answer:
To find the final concentration of the product, add the mass of benzoic acid and the mass of the ointment base, then divide by the volume of the ointment base.
Step-by-step explanation:
To find the final concentration of the product, we need to calculate the total mass and divide it by the total volume. The final mass is the sum of the mass of benzoic acid and the mass of the ointment base. The final volume is the volume of the ointment base.
Given: mass of benzoic acid = 18g, mass of ointment base = 103g
Total mass = 18g + 103g = 121g
Final concentration = total mass / final volume = 121g / 103g = 1.175g/g (or 1.175)