Biology; Chemistry; Physics: Post your doubts here!

[FLRNAB]

Oh god! just tell me am i thinking right or wrong :/

Sorry I didn't read properly. You are correct.

 

[Dark Destination]

Q1 ''And then extracted 25 cm of it... so 1/10th of the moles came in the 25 cm^3 of E.''
does that mean we took only 25 cm of that 250 solution that had water+vinegar?

We made it to 250, and then took 25 out of it, and the moles went to 1/10th of the original.

THEN, they made you calculate the moles in 25 cm^3 of E using mole ratios and titration.
And then in E, they asked how many their would be in 250 of E, you multiplied by 10.

and finally in f, they asked how many there would be in original vinegar solution, that would be same as E.

Hope you get it.

 

[princess Anu]

I got it ! thankyou
the only thing i don't understand is
when 25 of vinegar is added with water make E and the moles of ethanoic acid remain same.
then when 25 cm of E is taken the moles get divided.
WHY? even though this way we are changing the volume only but why then the moles aint same?
WHEN do the moles remain same in solutions ? ??

 

[princess Anu]

the moles of ethanoic acid in 25 cm of E and 250 cm of E are diff or same?

 

[Dark Destination]

I got it ! thankyou
the only thing i don't understand is
when 25 of vinegar is added with water make E and the moles of ethanoic acid remain same.
then when 25 cm of E is taken the moles get divided.
WHY? even though this way we are changing the volume only but why then the moles aint same?
WHEN do the moles remain same in solutions ? ??

When we add the water, the amount of moles remain in the solution, they don't escape.

But when we divide the solution, and take only 25 out of it, you are taking ONE TENTH of the volume of the solution out, so the moles in only ONE TENTH of the solution come out.
We assume that all the moles are spread evenly. All the ETHANOATE AND HYDROGEN IONS are spread evenly.

So when you take 25 out, only ONE TENTH of the ions come, and thus the moles are reduced ten times.

But when we add water, no moles escape. That's just the addition of water. Water further separates the ions, and they spread evenly out.

 

[areeb siddique]

no doubt preparations at peak only need prayers

loxD preparation hoti hai but paper aate hii haat per phool jatey hain!!

 

[Dark Destination]

the moles of ethanoic acid in 25 cm of E and 250 cm of E are diff or same?

Different

 

[FLRNAB]

18 Hours. O.O
Are you human or what?

I can barely study a few hours every day, like not more than 5, no matter how much i try, get distracted.

I manage my time. No not 18 hours. I am awake for 18 hours but 4 hours for other activities.

 

[Dark Destination]

I manage my time. No not 18 hours. I am awake for 18 hours but 4 hours for other activities.

Well, i believe Hard-work is not the key to success.
Praying with heart is. :')

 

[princess Anu]

Different

Why
maybe because 25 of E is division of that original 250 E?

 

[Dark Destination]

Why
maybe because 25 of E is division of that original 250 E?

Lol, do you want me to explain the entire thing again?
Read my above explanation..

 

[kirann]

Phew Glad to hear that

I'm reading a list of transition words

so did i,
how was your exam?

 

[Maganius]

so did i,
how was your exam?

Wrote more than the limit in both sections.
Chose 4th for Creative Writing.
Wbu?

 

[princess Anu]

Lol, do you want me to explain the entire thing again?
Read my above explanation..

No i understand it now. thanks a lot.

 

[kirann]

im stuck plz help

 

[Muhammad_Hamza]

Please help me in this part.
please show the working as well.

 

[kirann]

Wrote more than the limit in both sections.
Chose 4th for Creative Writing.
Wbu?

went good i have a doubt that i have wrote out of the limit in Q2
chose 6th

 

[princess Anu]

View attachment 41610 View attachment 41611 View attachment 41612
im stuck plz help

1: B
2: A
3: C
are these answers correct?

 

[kirann]

Please help me in this part.
please show the working as well.

this questiion is about the catalyst and i think it should be (a)
cuz no volume is increses using a catalyst, catalyst is not used up chemically in the reaction, so it will not react and no mass will decrease.

 

[Dark Destination]

I feel like i've forgotten chemistry