The number of molecules in 48.0 grams of oxygen gas (o2) is— A) 6.02 x 10^23
B) 9.03 x 10^23
C) 1.20 x 10^24
D) 1.81 x 10^24

i'm assuming that the correct answer is indeed the first one/ "a"..

d

explanation:

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