Chemistry: Post your doubts here!

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Can anyone help solve this, I used Mr=MRT/PV but I couldn't get a proper value.

When an evacuated glass tube of volume 200cm^3 is filled with a gas at 300k and 101kPa the mass of the tube increases by 1.06g.

What is the identity of the gas?

A) Argon
B) Krypton
C) Neon
D) Xenon
 
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View attachment 65257Can anyone explain the first point , and why’s its wrong and the third one
Heyy ... I had to ask for help because I was bamboozled by the fact that 1 is not correct. Here's the deal. 1 is wrong because the equilibrium pressure will only be reached once the external pressure (atmospheric pressure) is equal to the internal pressure .Work will be done by the expanding gas until the pressures inside and out even each other . This is an application of some Isobaric Processes Theory I suggest you look that up.

Number 3 can be explained in two ways . The English there was a bit tricky for me 😂😂😂 . (1)Well the expanding gas(from dissociation products) pushes back on the plunger and hence that is the increase in the volume there
(2) There's increase in moles of gases and since moles of gases directly proportional to the volume from PV=nRT thus theres a higher volume than there would be if no dissociation occurred
 
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Heyy ... I had to ask for help because I was bamboozled by the fact that 1 is not correct. Here's the deal. 1 is wrong because the equilibrium pressure will only be reached once the external pressure (atmospheric pressure) is equal to the internal pressure .Work will be done by the expanding gas until the pressures inside and out even each other . This is an application of some Isobaric Processes Theory I suggest you look that up.

Number 3 can be explained in two ways . The English there was a bit tricky for me 😂😂😂 . (1)Well the expanding gas(from dissociation products) pushes back on the plunger and hence that is the increase in the volume there
(2) There's increase in moles of gases and since moles of gases directly proportional to the volume from PV=nRT thus theres a higher volume than there would be if no dissociation occurred
I’m mind blown right now😂😂 that’s such an important pointer right there
Thank you so muchhh. I tried to research about any relationship between the equilibrium pressure and atmospheric pressure , but I couldn’t .
 
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Hello ,
Can anyone help solve this, I used Mr=MRT/PV but I couldn't get a proper value.

When an evacuated glass tube of volume 200cm^3 is filled with a gas at 300k and 101kPa the mass of the tube increases by 1.06g.

What is the identity of the gas?

A) Argon
B) Krypton
C) Neon
D) Xenon
check your conversions of pressure and volume , because I got 130.8 as the answer which I assume is for Xenon
 
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I’m mind blown right now😂😂 that’s such an important pointer right there
Thank you so muchhh. I tried to research about any relationship between the equilibrium pressure and atmospheric pressure , but I couldn’t .
I’m mind blown right now😂😂 that’s such an important pointer right there
Thank you so muchhh. I tried to research about any relationship between the equilibrium pressure and atmospheric pressure , but I couldn’t .
My Pleasure 😊😊

Yeah it doesn't appear much in textbooks but here's where I trust that you will find it

Its a textbook
 
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View attachment 65260

Can someone please solve part c (ii) and explain thanks in advance
c i) a yellow flame is seen . Since there's presence of the Sodium Ion so we expect the colour change when sodium is burnt ...

ii) We expect to see a blue solution. Since the basic CuO will react with the NaHSO4 to give NaSO4 + CuSO4 and water. We know for sure that Copper (ii) Oxide is basic(because it is an oxide of a metal) but you may be unsure about the acidity or basicity of HSO4-. The lewis structure of HSO4- shows that it has a hydrogen atom bonded to an oxygen atom . The Anion may act as a Brownsted Lowry acid and lose this proton(hydrogen) in chemical reactions because it has not undergone full deprotonation.(it would have undergone full deprotonation if it was SO4- . )
*Note that HSO4- is a derivative of SO4-

Therefore overall an acid base reaction will take place and we get a blue solution observed .
 
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