Biology; Chemistry; Physics: Post your doubts here!

[zohra`xo]

LOL B is the answer
as for Nitric acid it will give no reaction and for HCl will give White ppt of silver chloride

Don't get the HCl part.

 

[ZaqZainab]

Don't get the HCl part.

HCL had Chloride as the anions so test for Chloride is aqueous silver nitrite WHICH WILL GIVE white ppt

 

[Saad Mughal]

Don't get the HCl part.

Hydrogen, being more reactive will displace silver from the AgNO3 salt.

 

[zohra`xo]

Hydrogen, being more reactive will displace silver from the AgNO3 salt.

Ah. Got it. Thank you.

 

[Saad Mughal]

Ah. Got it. Thank you.

 

[ZaqZainab]

Hydrogen, being more reactive will displace silver from the AgNO3 salt.

i never taught of that i just learned the anions and cations test

 

[Saad Mughal]

i never taught of that i just learned the anions and cations test

You need to know the reasons (not for exams, for yourself) but this is quite simple.

 

[ZaqZainab]

You need to know the reasons (not for exams, for yourself) but this is quite simple.

but i don't have that in my book

 

[Saad Mughal]

but i don't have that in my book

Neither do I, but you need to know why the white precipitate (AgCl) forms.

 

[ahmed rockstar]

hey does any one have a link for chemistry guide or something??
and for physicsc too?? like for general revision points and reminders.......
your help is really appreciated

 

[Zuhsid]

So any guess paper for chemistry??

 

[passion hunter]

mole of Ca = 40/40 = 1 mol
mole of H2O = 100/18 = 5.6 mol ......so Ca is the limiting agent
total mass of sol remaining = mass of H2O left + mass of Ca(OH)2
mass of H2O reacted = 2 * 18 (mole ration) = 36......mass left = 100 - 36 = 64g
mass of Ca(OH)2 = RMM (as mol is 1) = 74
total = 74 + 64 = 138g

thank you so much!!

 

[passion hunter]

k here is the explaination.

40g of Ca = 1 mole. So it would react with two moles of water that is 36g. The rest of the water 100-36 = 64g is still left in the solution

now on the product side, 1 mole of Ca(OH)2 is formed. We can ignore the H2 as it is lost as gas. So mass of Ca(OH)2 is 74g
So, 64 + 74 = 138g

thanks a lot

 

[Suchal Riaz]

i)aqueous solid,liquid,gas
ii)moles of HCl 25/1000*1.5=0.0375
moles of CO2=1:2
x:0.0375
x=0.0375/2=0.01875 mol
vol=o.o01875*24000=45ocm3
i guess whts the ans in marking schemes

450 cm3 is the answer.

is it 450 cm3 ?

no answer of markscheme is 900cm² they did not divide by 2

 

[asma tareen]

no answer of markscheme is 900cm² they did not divide by 2

lol pehly mera 900 tha i wx like sab ka kyu 450 aaraha hai phr divide kia

 

[Suchal Riaz]

lol pehly mera 900 tha i wx like sab ka kyu 450 aaraha hai phr divide kia

dadi jan ka answer pehle likhti hein solve bad mein karti hein

 

[asma tareen]

dadi jan ka answer pehle likhti hein solve bad mein karti hein

 

[AhsanAfzal]

why is the answer d. is kinetic energy only produced when speed increases? Suchal Riaz

 

[Suchal Riaz]

why is the answer d. is kinetic energy only produced when speed increases? Suchal Riaz

K.E=1/2 mv²
when mass and velocity does not change the K.E does not change. but potential energy is decreasing as height is decreasing(P.E=mgh) therefore all of the energy is wasted as internal/heat energy or sound energy.

 

[AhsanAfzal]

K.E=1/2 mv²
when mass and velocity does not change the K.E does not change. but potential energy is decreasing as height is decreasing(P.E=mgh) therefore all of the energy is wasted as internal/heat energy or sound energy.

but isnt it still being produced? question says it is constant