Hello,my sample is 4.80grams of O2 with V of 15.0L. for the life of me (and going on two hours of trying...)what is the new V if 0.500 moles of O2 is added? Please don,t give the answer-comfort me only with your steps for solving. thank you, much amore'!
first step#1 convert grams to moles =4.80 x1/32g O2=0.15mol O2
step#2 add new mol to given mol 0.15+0.500 answ.0.65 or 65.0L I love myself
I suppose the P is constant. How many moles do you have in the 4.80 grams? That is moles = grams/molar mass. Call that n.
Use PV = nRT and solve for P with n from the 4.80 g sample. You don't have a T but use any number.
Then add 0.5 mole to what you have to start and use PV = nRT again. This time plug in P from the first calculation and use the same T, solve for V.
You can look at this another way
P = nRT/V so since P is equal we can set the two equal as in the following.
P=(n1RT/V1) = (n2RT/V2).
R and T cancel which leaves (n1/V1) = (n2/V2). Substitute and solve for V2.
Maryclare, the only problem with your solution is you were working for an answer. Your method won't cut it.
moles O2 is correct at 0.15 and you obtained that number properly.
Then the total moles is true, also, at 0.15+0.50 = 0.65 moles. But who says 0.65 moles is 65L? (and that's the correct answer).
holy smokes batman-I forgot a step-what do I do to get my answer? how DO I get the volume?
Well Batgirl, you can do it one of three ways. You can plug the numbers into (n1/V1) = (n2/V2)
(0.15/15) = (0.65/V2) and
V2 = (15*0.65/0.15) = 65L or you do it the long way I told you in the first response (the PV = nRT, solve for P, then PV = nRT again) to get 65 L, or a third way is to add a step to what you did. It would be done this way.
4.80/32 = 0.15 mole initially.
The ratio of 15L/0.15 mol = 100. So the new moles = 0.65; the ratio stays the same (because the P is staying the same) so 100 x 0.65 = 65L Voila. The last way is more esoteric. The first way is the least (just the use of the general gas law), the other way is between (part reasoning, part formula).
Sweet mother of Pearl,I get it.You leave me no choice but to spend two more hours just practicing this.
I hope your happy-heehee.
Seriously-YOU ARE AWESOME!
oh-and Thank you!I will be back.
Hello! I'd be happy to guide you through the steps to solve this problem. To find the new volume, you can use the ideal gas law equation, which states:
PV = nRT
Where:
- P is the pressure (which is not given in this case)
- V is the volume (the value you're trying to find)
- n is the number of moles of gas (0.500 moles in this case)
- R is the ideal gas constant (which has a value of 0.0821 L·atm/(mol·K))
- T is the temperature (which is not given in this case)
Since temperature is not provided, we can assume it remains constant. Therefore, we can simplify the equation to:
V1/n1 = V2/n2
Where:
- V1 is the initial volume (given as 15.0 L)
- n1 represents the initial number of moles (given as 4.80 grams of O2)
- V2 is the final volume (the value you're trying to find)
- n2 is the final number of moles (which is the sum of the initial number of moles and the additional moles added, 0.500 moles)
Now, let's plug in the values into the equation and solve for V2:
V1/n1 = V2/n2
15.0 L / (4.80 g O2 / (32.00 g/mol)) = V2 / (4.80 g O2 / (32.00 g/mol) + 0.500 mol)
First, we need to convert grams to moles by dividing by the molar mass of O2 (32.00 g/mol). Then, we substitute the values in and solve for V2.
I hope this explanation helps you work through the problem!