Asample of sugar (c12h22o11) contains 1.505 × 1023 molecules of sugar. how many moles of sugar are present in the sample?
a. 0.25 mol
b. 0.50 mol
c .1.00 mol
d. 2.50 mol

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