Question from destroyer chem

[DenTony11235]

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Referencing problem 98, the problem mentions 4 beta decays... How are we supposed to know that the beta decay is a positron emission rather than an electron emission...

Also, since k is only effecting by changes in temp. Why wouldn't changing the pressure and volume of a container indirectly effect k through changing the temp?

 

[two thirty]

Do you mind posting the specific question and answer choices?

Second part:

I'm assuming you're looking at the PV=nRT equation. k is just the equillibrium constant. Temperature is the only thing that alters the constant itself. An increase in P could still leave T at a constant if it lowered P or increased n.

 

[DenTony11235]

Sure thing. The question word for word is a nuclide 225-90 Th underwent 3 alpha decays, 4 beta decays and a gamma decay. What is the resulting nucleus? Radon, radium, antimony, cadmium, actinium.

Maybe it's because the alpha decays left a positively charged atom, and only electron emissions would stabilize the atom into a neutral one? That's my take, id like to see if that is the official way of doing these problems.

 

[DenTony11235]

But taking into consideration gay Lussacs law, pressure and temperature are directly proportional, so if pressure increases shouldn't temperature increase along with it?

 

[IsaacYankem]

225/90 Th --> 3 alpha, 4 beta, 1 gamma [ignore, who cares]

225/90 Th --> 3(4/2)a + 4(0/-1)b + X = 12/6 + 0/-4 + X = 225/90 Th --> 12/2 + X

225/90 - 12/2 = 213/88

Beta Decay converts neutron --> proton. Just write out the reaction and balance the equation to keep this straight and avoid in confusion. If the question stated positron emission, you'd have 213/80 instead. Hope that helps.

 

[DenTony11235]

225/90 Th --> 3 alpha, 4 beta, 1 gamma [ignore, who cares]

225/90 Th --> 3(4/2)a + 4(0/-1)b + X = 12/6 + 0/-4 + X = 225/90 Th --> 12/2 + X

225/90 - 12/2 = 213/88

Beta Decay converts neutron --> proton. Just write out the reaction and balance the equation to keep this straight and avoid in confusion. If the question stated positron emission, you'd have 213/80 instead. Hope that helps.

I guess ill just go by those rules for beta emission. I was just taught that beta emission is positron emission. Royally screwed my brain up.

 

[IsaacYankem]

My understanding is beta decay = 0/-1 as a product, Positron emission as 0/1 as a product, and e- capture as 0/-1 as a reactant. If there are any inaccuracies here, please let me know as I haven't taken chemistry in years

 

[DenTony11235]

My understanding is beta decay = 0/-1 as a product, Positron emission as 0/1 as a product, and e- capture as 0/-1 as a reactant. If there are any inaccuracies here, please let me know as I haven't taken chemistry in years

Seems legit

 

[DenTony11235]

My understanding is beta decay = 0/-1 as a product, Positron emission as 0/1 as a product, and e- capture as 0/-1 as a reactant. If there are any inaccuracies here, please let me know as I haven't taken chemistry in years

Seems legit. Ill go by that from now on. Thanks