Question

How many milligrams of sodium thiosulfate (m.w. = 158) are represented by 0.25 mmol? (answer must be numeric; no units or commas; include a leading zero when answer is less than 1; round final answer to the nearest tenth.)?

Answer 1

To calculate for mass, simply multiply molar weight (MW) and number of mols. The molar weight (MW) is in units of mg / mmol. Therefore the mass is:

mass = (158 mg / mmol) (0.25 mmol)

mass = 39.5 mg

Answer:

39.5