Final answer:
To find the amount of salt in 300 g of seawater with a 3.5% NaCl concentration, multiply the mass of seawater by the percentage of NaCl (300 g × 0.035), resulting in 10.5 g of salt. The correct answer is option A.
Step-by-step explanation:
To calculate the amount of salt that can be obtained from 300 g of seawater with a NaCl concentration of 3.5% by mass, we can use the formula:
Mass of NaCl = Mass of seawater × Percentage of NaCl in seawater
Substituting the given values:
Mass of NaCl = 300 g × 0.035
Mass of NaCl = 10.5 g
Therefore, the amount of salt that can be obtained is 10.5 g, which corresponds to option A.
It is important to note that the mass of NaCl must be weighed out and subtracted from the mass of the saline solution to calculate the mass of water that would need to be added when making a solution.