What is the significance of the half-life of a radioisotope? O A. It tells what fraction of a radioactive sample remains after a
certain length of time.
B. It tells how long a radioisotope sample is considered dangerous.
C. It tells how much energy is released over the lifetime of a
radioactive sample.
D. It tells what kind of radioactivity is released through radioactive
decay.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa

c. is the answer

by love gaming

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