Why would a doctor most likely restrict a patient’s contact with other people while the patient receives internal radiation? A. The patient’s stress and anxiety would be eliminated.
B. High levels of radiation can diffuse through the patient’s skin.
C. Social contact would increase the effect of the radiation treatment.
D. Radioactive material can leave the patient’s body through saliva, sweat, and urine.

D

the answer is minerals.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol