Gchem question

[Faux]

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I think I'm just having a moment but I'm having trouble with this question

At constant atmospheric pressure, 3.0L of helium gas is heated from 27°C to 127°C. What is the volume of the gas at the new temperature?

I understand that Volume and temperature are proportional. I'm just having a hard time wrapping my head around the math that was done


V2=(3.0 L)(400 K) / 300 K=4.0 L

Basically its (T1)(V2) = (T2)(V1). Why is it like this?

 

[LazyP]

Combined gas law derived from PV=nRT* states [(Pi)(Vi)]/(Ti) = [(Pf)(Vf)]/(Tf) where i = initial and f = final. Constant pressure thus u can get rid of P since it does not change (i = f) so its Vi/Ti = Vf/Tf

* [PiVi]/[nTi] = R = [PfVf]/[nTf] since R is always a constant and cancel n (not adding additional moles) so it becomes the combined gas law

 

[Eri3]

I think I'm just having a moment but I'm having trouble with this question

At constant atmospheric pressure, 3.0L of helium gas is heated from 27°C to 127°C. What is the volume of the gas at the new temperature?

I understand that Volume and temperature are proportional. I'm just having a hard time wrapping my head around the math that was done


V2=(3.0 L)(400 K) / 300 K=4.0 L

Basically its (T1)(V2) = (T2)(V1). Why is it like this?

The great thing is for most ideal gas problems you barely have to do any math. Think about it in terms of PV = nRT

Everything on the left of the equal sign is directly proportional to everything on the right side of the equal sign and vice versa.

Everything on the same side of the equal sing are inversely proportional to one another.

Thus in this case. Holding everything else constant V is proportional to T - what ever you do to V, you must do to T.

Tinitial = 300 K ------> T final = 400K

Since V is proportional to T - if T went from 3 to 4 so must V. Thus Vfinal = 4L
Vinitial =3L -------> Vfinal =x