You're performing a titration of some acetic acid. You have reason to doubt that the grocery store is selling you vinegar at the concentration listed on the label. The label says the contents are 2.00M acetic acid. You begin performing the titration on 5mL of the acetic acid sample with 0.48M NaOH. You perform the titration and find that your indicator (phenolphthalein) turns the slightest shade of pink and determine you've added 37.4mL of the 0.48M NaOH.

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.

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