Final answer:
The mass of NaCl in 51.2 mL of a 10.0% w/v solution is calculated using the definition of percent concentration, yielding 5.12 grams.
Step-by-step explanation:
To find the mass of NaCl in a 10.0% w/v solution, we use the definition of percent concentration. A 10.0% w/v solution of NaCl means that there are 10 grams of NaCl in every 100 mL of solution. Since the question provides us with a volume of 51.2 mL, we can set up a proportion to find the mass of the NaCl.
Mass of NaCl = (mass of NaCl in 100 mL) × (volume of the solution in mL) / 100 mL
Given that in 100 mL of solution there is 10.0 g of NaCl, we can calculate the mass for 51.2 mL:
Mass of NaCl = 10.0 g × 51.2 mL / 100 mL
Mass of NaCl = 5.12 g
Therefore, the mass of NaCl in 51.2 mL of a 10.0% w/v solution is 5.12 grams.