However, there is a problem. We are asked to change the conditions for a new amount of moles and pressure. It therefore seems that the ideal gas law should be applied twice. Note that in the two problems above, I converted the unit of pressure specified in the problem to atmospheres. I did this to use the value for R that I memorized. There are many different ways to express R, it`s just that L-atm/mol-K is my favorite unit whenever possible. Also, you cannot use molar volume because the above two issues are not related to STP. 1) Note that the problem requires two conditions: one of temperature and one of pressure. The answer we arrive at is not a value of T and a value of P, but a relationship between the two. Start here: Converting to Celsius and using four Sig figs gives 362.5°C for the answer. Depending on the units chosen, the „value” of R can take many different forms. Here is a list. Remember that these different „values” represent the same thing.
1) To find the conversions, divide one by the other: 2) Divide the specified grams (96.0) by the moles calculated above: Sometimes it is called the universal constant because it appears in many non-gas situations. However, it is usually referred to as the gas constant or sometimes the universal gas constant. 3) Since the question mentions T first, let`s determine a T/P ratio: 5) I will isolate T2 on one side of the equal sign: Warning: You can only use molar volume when you are at STP. This second equation uses the data from the second sentence and T2 is the unknown. 1) Which gas law should be used to solve this problem? This equation uses the amount of 2.035 g of H2 as well as the 1.015 atm, 5.00 l and -211.76 °C (converted to Kelvin, which I will do shortly). Any combination T/P equal to 136.57 is a response. 4) If you want a P/E ratio, it would be 0.007322. 4) I will use the fact that R is the same value in each equation: 3) Since it is STP, we can also use the molar volume: this problem, as well as the two mentioned above, can be solved with PV = nRT. They would solve for n, the number of moles.
Then you would divide the grams given by the calculated mole. What I need to do is put the two equations on an equal footing. First of all, I`m reorganizing a bit.