Chemistry MCQ thread...

[abdullah181994]

plz help me at this......................
help me find which transportable gas is poisonous

i think its d

 

[workinghard]

@wahab i dont think any is poisonous dey r flammable!

 

[rahultaneja2010]

Can someone help me find the shapes of the following :
1) alcl3
2) ch3+
3) ph3

Pls show how u worked it out thanks .... Inshallah

1 and 2 have trigonal planar shape ( 120 degrees between the bonds because there are no lone pairs on the Al and C atoms ). PH3, it has 1 lone pair so the angle should be 107 but i remember one question they showed the angle as 104, i heared that this question was removed but anyways these are the shapes and angles

Thank u very much , how do u kno ph3 has 1 lp ??

 

[hassam]

zishi...all bond making processes are EXOTHERMIC Apart from exceptions....so formation of H-CL is most exothermic since H-Cl bond strength is high and it decreases DOWN THE GROUP ......I.E LESS EXOTHERMIC AND IN CASE OF HI IT BECOMES ENDOTHERMIC SINCE h2 and I2 BONDS INVOLVE MORE ENERGY IN BREAKING THAN THAT RELEASED ON FORMATION OF hi bond

 

[meoooow]

7 Flask X contains 5 dm3 of helium at 12 kPa pressure and flask Y contains 10 dm3 of neon at 6 kPa pressure.
If the flasks are connected at constant temperature, what is the final pressure?

A 8 kPa B 9 kPa C 10 kPa D 11 kPa

hey can someone please help me with this?

 

[Xthegreat]

nope, PH3 is 104 not 107. NH3 is 107.

although both have trigonal pyramidal shape the main reason for the difference is
- N is more electronegative than P
- bonding electrons are closer to N than in P
- the electrons are closer hence the bonds in N experiences a greater repulsion than in P

 

[Mobeen]

@wahab no gas is poisonous .. and the question is for flamable gases .. so only one is non flamable and others are flamable ..

 

[hassam]

a small spacecraft of capacity 10 m*3 is connected to another of capacity 30m*3.......b4 connection,the pressure inside smaller one is 50 kPa and 100 kPa in larger one...wats the final pressure.....
A. 75
B 87.5
C 100
D 125

 

[xHazeMx]

a small spacecraft of capacity 10 m*3 is connected to another of capacity 30m*3.......b4 connection,the pressure inside smaller one is 50 kPa and 100 kPa in larger one...wats the final pressure.....
A. 75
B 87.5
C 100
D 125

B

 

[rahultaneja2010]

B

 

[meoooow]

13 In aqueous solution, the acid HIO disproportionates according to the following equation where m,
n, p and q are simple whole numbers in their lowest ratios.
mHIO → nI2 + pHIO3 + qH2O

This equation can be balanced using oxidation numbers.
What are the values for n and p?
n p
A 1, 2
B 2 ,1
C 4 ,1
D 4 , 2

and this!

 

[Abdulrab]

please do this question Q2 of Oct /Nov 08 !! its challenging

ao i think u all should try it and give me the correct answer !!! thnx please do it asap !!!

heres the link also ! http://www.xtremepapers.me/CIE/Internat ... 8_qp_1.pdf

 

[hassam]

HOW DID U DO

 

[abdullah181994]

plz help me at this......................
help me find which transportable gas is poisonous

which year question it is

 

[rahultaneja2010]

Use formula p1v1 + p2v2 = p3v3 , v3 is total volume

 

[wahab305]

plz help me at this......................
help me find which transportable gas is poisonous

its OXYGEN .. obviously oxygen cant burn IN OXYGEN ..

oh buddy dont be in a fuss read the question first..................

 

[Saturation]

For all those questions which ask final pressure or volume:

I use the formula: (P1 x V1) + (P2 x V2) = (P3 x V3)

P1 and P2 , being the pressures of the initial containers and P3 being the final pressure when they are connected together.
V1 and V2 being the volumes of the initial containers and V3 being the final volume when they are connected together.

Just apply it!

 

[hassam]

 

[Saturation]

Someone help me out!:
http://www.xtremepapers.me/CIE/Internat ... 5_qp_1.pdf

question 25, whats the difference between A and D? For PCl5 to react with the molecules, they must contain the alcohol group right?

 

[hassam]

COOH GRoup also reacts with pcl5