Arenowned laboratory reports quadruple-point coordinates of 10.2 mbar and 24.1°c for four-phase equilibrium of allotropic solid forms of the exotic chemical β-miasmone. is the claim valid or not?

Explanation:

We should have an invariant point condition (The degree of freedom F=0 as per phase rule) for a quadruple point to occur and to test whether this argument is valid or not we must implement phase rule in a given case.

So, as per the Phase Principle F= C-P+2 Here in this situation all types are allotropic implying they consist of the same chemical compound, i.e. each have the same chemical composition.

Then constituents C=1,  P= 4 (because they have 4 phases) Also no parameters for the given system are 2, Pressure and Temperature, these are found by including 2 in the formula of phase rule

Therefore,  F= 1-4+ 2=-1 is certainly not equal to 0 and therefore the claim that they found a quadruple point is counterfeit.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e