Which is NOT pseudoscience?

Ghosts
Astrology
UFOs
Astronomy

Astronomy

Explanation:

The reason why is because, ghosts aren't real unless proven otherwise but, currently there is no proof, there hasn't really been any proof of UFO's because, currently that is just a speculation, astrology is the study of stars but, saying things like if you see a circle of stars then there will be a war. (I made that up but its an example) There are no proof for those three but, astronomy is real because, it is the study of stars and planets basically what NASA does.

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