Reactions and ions.
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d the evolution of
actions are one
affected by
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Chemical reactions involve the loss, gain, or
sharing of electrons, but do not involve
changes to the nucleus of an atom.
Nuclear reactions involve nges to the
nucleus and produce a new particle.
Chemical reactions involve low energy
changes.
Chemical reactions never involve a change in
the mass of atoms.
Nuclear reactions often involve a change in
the mass of an atom.
DONE
5 of 12

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