Final answer:
To find the mass of salt in a 250-gram sample of a 3.0% saltwater solution, you multiply 250 grams by 0.03, resulting in 7.5 grams of salt. Therefore correct option is D
Step-by-step explanation:
To calculate the amount of salt in a sample of saltwater solution with a concentration of 3.0% (w/w), you multiply the total mass of the sample by the percentage of salt. In this case, you have a 250-gram sample, so you calculate the mass of salt as follows:
Mass of salt = 250 grams × 0.03 (3.0%)
= 7.5 grams
Therefore, the correct answer to how much salt there is in a sample which weighs 250 grams of a 3.0% saltwater solution is option d. 7.5 grams.