At 1 atm, equal masses of h₂o(s), h₂o(l), and h₂o(g) have
(1) the same density
(2) the same distance between molecules
(3) different volumes
(4) different percent compositions

i dont know the answe

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

answer carbon and three oxygen atoms;