A balloon filled with 0.01 mol of hydrogen gas is kept constant at 25 degrees Celsius. If the pressure is increased from 1atm to 1.5atm, what is the resulting volume?
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C3H8(g) + 5 O2(g)-->3 CO2(g) + 4 H2O(g)
A 0.03 mol sample of C3H8 is reacted with just enough O2 to use up both reactants in a 1L flask at 300 K. The total pressure in the flask after the reaction is complete is closest to whih of the folowing... (Use R = 0.082)
A) 5.0
B) 0.5
C) 0.1
D) 0.25
E) 0.05
a)
Use PV = nRT
P = 1.5 atm
solve for V
n = 0.01 mols
R = 0.08205 or whatever your teacher has said to use for this number but the units must be in L*atm/mol*K if you use atm for pressure.
T = 298.
I found V about 0.16
b)
Use PV = nRT
Solve for P.
V = 1L
R = 0.082 from the problem.
T = 300 K
n = 0.21
(For every 1 mol C3H8 we get 7 mols, combined, of H2O (as a gas) and CO2 (as a gas). We started with 0.03 mols C3H8; therefore, 7 x -./03 = 0.21
A couple of additions to my post.
The 0.16 for (a) is approximate and the unit is liters.
For (b), I made two typos in the last line. It should read "We started with 0.03 mols C3H8; therefore, 7 x 0.03 = 0.21 mols of gas.
So basically they said "pressure is changed from 1atm to 1.5atm" to confuse you?
and thank you so much for the response. It helped me understand it A LOT more. =]
I suppose that is right, more or less. It really doesn't matter WHAT the pressure was at the start although we could have calculated it if necessary.
Ah, the pressure was just a distraction, like the magician saying, "Look over here!" while doing something sneaky. But don't worry, I'm here to help you see through the tricks! And I'm glad I could help you understand it better. Remember, chemistry doesn't have to be a scary circus act – with a little humor and some practice, you'll be juggling those equations like a pro! 🎪🤡
Yes, that's correct. In this case, they just want you to calculate the resulting volume when the pressure is increased from 1atm to 1.5atm. The initial pressure doesn't play a role in the calculation since it's not needed to find the final volume. So you can just focus on using the given values (P = 1.5 atm, n = 0.01 mol, T = 25 degrees Celsius or 298 K) to solve for the final volume using the ideal gas law equation, PV = nRT.
Yes, in the first question, the initial pressure of 1 atm is given to provide context, but it is not necessary to calculate the resulting volume. The change in pressure from 1 atm to 1.5 atm is what matters in determining the resulting volume.
I'm glad that my response was helpful in explaining the solution to you! Feel free to ask if you have any more questions.