Biology; Chemistry; Physics: Post your doubts here!

[ashiqbal]

Which gas contains the same number of molecules as 9 g of water?
A 2 g of hydrogen
B 14 g of nitrogen
C 32 g of oxygen
D 44 g of carbon dioxide

its B) : 9/18 =14/28

 

[ashiqbal]

no change

wrong answer!

 

[A star]

Which gas contains the same number of molecules as 9 g of water?
A 2 g of hydrogen
B 14 g of nitrogen
C 32 g of oxygen
D 44 g of carbon dioxide

b as .5 moles of nitrogen gas

 

[A star]

wrong answer!

either that or concentrate it

 

[ashiqbal]

either that or concentrate it

why would it become more concentrated?can u explain that please?

 

[A star]

why would it become more concentrated?can u explain that please?

because ions from water are being electrolysed so sutomatically it will concentrate i thought first that water produced at anode would be suficent to replace lost water but it is not

 

[ashiqbal]

because ions from water are being electrolysed so sutomatically it will concentrate i thought first that water produced at anode would be suficent to replace lost water but it is not

k thanx

 

[malay]

The mass of one mole of a chloride formed by a metal Y is 74.5 g.
What is the formula of the chloride?
A Y3Cl
B Y2Cl
C YCl
D YCl 2

 

[kitecrystal]

Since there will be no double displacement, for e.g if you chose to react KNO3 with HCl, the H wont be able to displace K nor will the Cl be able to displace NO3 hence no reaction will take place.[/quote
thanku

 

[kitecrystal]

i guess coz both the products formed are soluble
e.g
KNO3(aq)+HCl(aq)--->KCl(aq)+HNO3(aq)
KNo3(aq)+AgCl(s)--->KCl(aq)+AgNO3(aq)
its not suitable as we cant seperate them....
(correct me if m wrong)

in titration method reactants are all soluble.

 

[kitecrystal]

may because to
link fr qstn pls? kite

june 2006 B9(b)..,in examiner report,it is written that KNO3 was wrongly chosen as a reactant..

 

[kitecrystal]

in titration method reactants are all soluble.

Topic people, back on topic.
View attachment 11042View attachment 11043

31.B because 20% oxygen present in air is used up.Rest of 80%is left which is 64cm^3.

 

[Nashit Akhter]

ANY IMPORTANT CHAPTERS FOR CHEMISTRY OR ANYONE HAS WAHAJ HUSSAIN CHEMISTRY MOCK PAPER.....................!!!.....................

 

[daredevil]

The mass of one mole of a chloride formed by a metal Y is 74.5 g.
What is the formula of the chloride?
A Y3Cl
B Y2Cl
C YCl
D YCl 2

woww .... that's tough!!
umm.... iss this the total answer?? and also the mass is for the salt formed?? or is it for the cloride ions in the salt??

 

[asd]

woww .... that's tough!!
umm.... iss this the total answer?? and also the mass is for the salt formed?? or is it for the cloride ions in the salt??

Its C.
74.5 -35.5 = 39 which is potassium .
So YCl.
malay

 

[ISFSAT]

i want to ask.. that in the conventional curent and the electron flow mcq...which heading was in the table first???
conventional current or electron flow.............

 

[a.abid]

i want to ask.. that in the conventional curent and the electron flow mcq...which heading was in the table first???
conventional current or electron flow.............

electron flow I guess

 

[Spidey21]

i want to ask.. that in the conventional curent and the electron flow mcq...which heading was in the table first???
conventional current or electron flow.............

 

[ayeshaK]

http://www.xtremepapers.com/papers/...nal O Level/Physics (5054)/5054_w10_qp_42.pdf
Can nybdy explain yhe graph ! Question 2 ci)
I have made it but still confirming !!

 

[ISFSAT]

actually i want to confirm that what was in the first column.... conventional current or electron flow.....