The Correct Use of English Articles [duplicate]

Fill in the right articles: A, An, the, Ø.

Boyle's law states ____ pressure of ____ gas is inversely proportional to ____ volume of ____ gas ____ constant temperature.

I Agree to @my name's response to this question. As @my name explains pressure and volume are specific to gas, so we use "the." But what about "temperature". Should it be "the constant temperature" or "constant temperature?"

Also, temperature, pressure, and volume are all uncountable nouns. Thus, indefinite articles (a and an) does not follow them. But take a look at the sentence below from Wikipedia. In which indefinite article "a" follows them. This really confuses me.

Solution 1:

Boyle's law states the pressure of a gas is inversely proportional to the volume of the gas.

In this case we are referring to an arbitrary gas in the first instance, hence the 'a'. This arbitrary gas has only a single pressure associated with it, so we refer to it as 'the' pressure. The second reference to gas is again to that same gas in the first instance, so we again use 'the' to show that it is a specific gas. Finally, the gas again only has one volume so we refer to that volume specifically with 'the'.

The second instance of gas may be confusing, and in this case a clearer option might be:

Boyle's law states the pressure of a gas is inversely proportional to the volume of that gas.