Which of the models shown below best represents the modern understanding of the structure of the atom? Two small green balls and two small red balls labeled with plus signs are clustered at the center of a larger circle. Two small yellow circles labeled with minus signs lie on the outer circle, directly across from each other.
Model A

A red ball is shown, with a plus sign faintly visible on it. The ball contains 10 smaller orange balls, each labeled with a minus sign.
Model B

Atomic Structure
Model C

Photos by Phrood and Furmanj

Model A

Model B

Model C

fr8t7iot7o87oglgt87ot79p0[90

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

the answer is 0.42 is that is an option. this question provides no info