Answer :
It would take 0.827 g of arsenic to reach the LD50 in a 140-pound person.
The lethal dose 50 (LD50) for arsenic in humans is 13 mg/kg.
What is the LD50?
LD50 is the amount of a material, given all at once, which causes the death of 50% of a group of test animals.
To calculate the number of grams of As that it would take to reach the LD50 in a 140-lb person, we need to convert 140 lb to kg using the conversion factor 1 lb = 0.454 kg.
140 lb Ă— 0.454 kg/1 lb = 63.6 kg
The LD50 of As is 13 mg of As per kg of body mass. The mass of As to reach the LD50 in a 63.6-kg is:
63.6 kg BM Ă— (13 mg As/1 kg BM) Ă— (1 g As/1000 mg As) = 0.827 g As
It would take 0.827 g of arsenic to reach the LD50 in a 140-pound person.
Learn more about LD50 here: https://brainly.com/question/8136561