Final answer:
The final concentration of the mixture obtained by combining 9 ml of an 80% saline solution and 6 ml of a 30% saline solution is 60%.
Step-by-step explanation:
The question involves finding the concentration of a mixture of two saline solutions with differing concentrations. To calculate this, we use the concept of mass/volume percent and the principle of mass conservation. The total mass of the solute (NaCl) in the new solution is the sum of the solutes from both solutions before mixing. Therefore, we calculate it by adding the mass of NaCl in each solution: (9 ml × 80% for the first solution) + (6 ml × 30% for the second solution). The total volume of the new solution is the sum of the volumes of the two solutions (9 ml + 6 ml). The final concentration can then be found by dividing the total mass of NaCl by the total volume of the mixture and converting the result into a percentage.
The calculation is as follows:
Total mass of NaCl = (9 ml × 0.8) + (6 ml × 0.3) = 7.2 + 1.8 = 9 grams of NaCl
Total volume of the mixture = 9 ml + 6 ml = 15 ml
Final concentration = Total mass of NaCl / Total volume of mixture × 100% = 9 g / 15 ml × 100% = 60%