Which equation describes a reduction? Upper M g (s) right arrow Uper M g superscript 2 plus (a q) plus 2 e superscript minus. 2 upper C l plus 2 e superscript minus right arrow 2 upper C l superscript minus. Upper N a (s) right arrow upper N a superscript plus (a q) plus e superscript minus. Upper A l (s) right arrow upper A l superscript 3 plus (a q) plus 3 e superscript minus.

the answer

explanation:

the capillary tube was too close to the bottom of the beaker.

the ruler may have moved.

water got into the capillary tube.

the temperature was not allowed to equilibrate in the 2-4 minutes.

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .

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