Suppose an aspirin™ tablet contains 7 grains of the active ingredient, acetylsalicylic acid (1 grain = 64.7989 mg). if your tablet had a mass of 516 mg, calculate the percent recovery if you isolated 386 mg of acetylsalicylic acid in this experiment.

85.105 is the percent recovery if you isolated 386 mg of acetylsalicylic acid in this experiment.

Explanation:

Number of grains of acetylsalicylic acid = 7 grains

(1 grains = 64.7089 mg)

7 grains = 7 × 64.7089 mg = 453.5923 mg

Total mass of acetylsalicylic acid = 453.5923 mg

Total mass of tablet = M = 516 mg

Mass of acetylsalicylic acid recovered = 386 mg

The percent recovery of acetylsalicylic acid recovered:

85.105 is the percent recovery if you isolated 386 mg of acetylsalicylic acid in this experiment.

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