What is the correlation between pressure and elevation for an ideal gas?
p=p(z), p=pressure, p(z)=elevation

Explanation:

Expression for vertical fluid pressure is as follows.

                ........... (1)

where,     p = pressure

            = density

               g = acceleration due to gravity

               h = height

Since, g is negative then it means that an increase in height will lead to decrease in pressure.

Also, expression for density according to ideal gas law is as follows.

                  .......... (2)

where,         m = average mass or air molecule

                    P = pressure at a given point

                    k = Boltzmann constant

                    T = temperature in kelvin

Substituting values from equation (2) into equation (1) as follows.

Now, on applying integration on both the sides we get the following.

or,                                              

where,           = pressure at height h

                      = pressure at reference point    

Thus, we can conclude that the correlation between pressure and elevation for an ideal gas is  .        

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

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

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