You are trying to boil water while camping in the colorado rockies. the surrounding barometric pressure is 0.9 bar, and the water is currently boiling. using gibb's phase rule, the system is under specified over specified perfectly specified

Perfectly Specified

Explanation:

Pressure, P = 0.9 atm

Boiling point = T

Number of components C = 1

Number of phases P = 2

Using  Gibbs phase rule as:

F = C - P + 2

F = 1 - 2 + 2 = 1

At Pressure = 0.9 atm, boiling point is T which means that the temperature is also fixed which is equal to 96.7 °C . The data taken from steam table.

In given problem, the pressure is fixed so temperature is also fixed.

The system is perfectly specified.

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