Arturo recently read about watersheds and the direction rivers flowed in the United States. Arturo studied his map of the country and identified rivers and their flow direction. Look at the picture and identify what the black line drawn on the map representsA. the water flow B. the Great Divide
C. the Great Basin
D. the Mississippi Riv

the answer is   c.) 1575 j.

explanation:

the answer is d.) potassium

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