A P. answered • 03/23/20
Tutor
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Chemical engineer with 15+ years of chemistry teaching experience
PV = nRT
I am going to divide the equation by itself and assign 1s and 2s for the two states.
P1V1/P2V2=n1RT1/n2RT2. T1=T2, P1=P2, so we can get rid of those along with R since that is constant.
V1/V2=n1/n2. n1=0.40 mol, and V2=0.9V1 (10% loss = 90% remaining). Let's sub this in.
V1/0.9V1=0.40mol/n2. Simplify to 1/0.9=0.4/n2. Solve for n2 = 0.36 mol.
Let me know if this makes sense or if you have questions - we can also always jump on a quick call.
A P.
tutor
So, yes and no. This answer makes sense if it drops TO 10%, not BY 10%. I usually despise blaming the question, but in this case, it is worded poorly. Apart from that, the method is the same. The one thing I did not do is convert from moles to grams. Let me know if that makes sense. Steps are shown below.
P1V1/P2V2=n1RT1/n2RT2. T1=T2, P1=P2, so we can get rid of those along with R since that is constant.
V1/V2=n1/n2. n1=0.40 mol, and V2=0.1V1 (loss TO 10%). Let's sub this in.
V1/0.1V1=0.40mol/n2. Simplify to 1/0.1=0.4/n2. Solve for n2 = 0.040 mol.
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03/23/20
Sandra R.
this is the answer I was given after putting in the incorrect one. Avogadro's Law states that the volume of a confined gas is proportional to the number of moles of gas at constant temperature and pressure. Therefore, if the volume drops by 10. percent, the number of moles will drop by 10. percent. Multiply the number of moles by 0.10 to find the moles that escaped the balloon. 0.40moles×0.10=0.040moles Now convert 0.040moles to grams of helium by multiplying by the molecular weight of helium, 4.00grams/mole. 0.040moles×4.00grams/mole=0.16grams03/23/20