Chemistry: Post your doubts here!

[Hamnah Zahoor]

h

how do you know this?

Well option C is a hydrogen cyanide H single bonded to carbon and carbon bonded with a triple bond to nitrogen.

 

[SohaibButt]

Here one of the product View attachment 64004

Thanks

 

[SohaibButt]

Here one of the product View attachment 64004

Can u recommend me which year paper u faced comparatively difficult?

 

[khadijaimran]

can someone explain this? ans is B

 

[Kanekii]

can someone explain this? ans is B

Any combination of ester can be formed in multiples of 3 as the orginal ester has 3 carbon atoms but statement/option three has 5 carbon atoms in its ester so therefore it is wrong.

 

[Kanekii]

in an experiment a sample of a pure gas is put into a gas syringe at a temperature of 300K and pressure of 16 kpa. the gas is compressed until the volume occupied by the gas is halved.
after the compression, the temperature of the gas in syringe is 375 and the pressure is 40 kpa.
is the gas is ideal

No it is not ideal as for a gas to be ideal it has to have high temperature and low pressure even though the temperature has rised its pressure has increased greatly.

 

[sukasukinya]

Please First tell me is the answer to this question option C .
sp-triple bond
sp2 - double bond
sp3 - single bond

Thank youuu so much

 

[Kanekii]

Umm i have a question i know its pretty silly etc but what do we do for a diatomic molecule like for example O2(oxygen) i get that it will have a Mr of 32 but what about the moles and volume would we consider 1 mol and 24dm3 for it?

 

[A*****]

Umm i have a question i know its pretty silly etc but what do we do for a diatomic molecule like for example O2(oxygen) i get that it will have a Mr of 32 but what about the moles and volume would we consider 1 mol and 24dm3 for it?

Yes Mr will be 32 and will be considered 1 mol occupying 24dm³ of volume at room temp and pressure

 

[A*****]

Help plz

 

[Daniel Avarro]

No it is not ideal as for a gas to be ideal it has to have high temperature and low pressure even though the temperature has rised its pressure has increased greatly.

It is ideal. If you use the equation. P1V1/T1 = P2V2/T2 you get that they are equal.

WORKING
----------------
V2 = v1/2(volume halved)

16V/300 = (40v/2)/375

You get the answer that both are equal

 

[Daniel Avarro]

Help plz


View attachment 64006

Since it is 1cm3, the mass is 1g(density is 1g/cm3) the moles of water in 1g is 1/18 = 0.0556.
1 mole uses 24dm3. Therefore, 0.056 moles uses 0.0556 x 24 = 1.33dm3.
Now, that is for 298K. We need to find it for 596K.
Since pv=nRT, n is proportional to Temperature
so 596/298 x 1.33 = 2.67dm3

 

[Ebrahim12]

oct nov 2008

Q 38. Which of the following would be suitable for use in a fire extinguisher?
1 CBrF 3
2 CH3(CH2)5CH2Br
3 HCl

Only statement 1 is correct, how come 2 isn't?

 

[Hamnah Zahoor]

oct nov 2008

Q 38. Which of the following would be suitable for use in a fire extinguisher?
1 CBrF 3
2 CH3(CH2)5CH2Br
3 HCl

Only statement 1 is correct, how come 2 isn't?

statement 2 also have a long hydrocarbon chain which is more flammable.
Thus provide no use as a fire extinguisher.

 

[A*****]

statement 2 also have a long hydrocarbon chain which is more flammable.
Thus provide no use as a fire extinguisher.

What about 3?

 

[Hamnah Zahoor]

What about 3?

Only bromine containing compounds and carbondioxide are used as fire extinguishers.
Acids are not used.

 

[IN NEED OF HELP]

In an experiment, 12.0dm3 of oxygen, measured under room conditions, is used to burn completely 0.10mol of propan-1-ol. What is the final volume of gas, measured under room conditions? A 7.20dm3 B 8.40dm3 C 16.8dm3 D 18.00dm3 ans is B. Pls explain how

 

[A*****]

In an experiment, 12.0dm3 of oxygen, measured under room conditions, is used to burn completely 0.10mol of propan-1-ol. What is the final volume of gas, measured under room conditions? A 7.20dm3 B 8.40dm3 C 16.8dm3 D 18.00dm3 ans is B. Pls explain how

 

[Kanekii]

Is the boiling point of a compound directly proportional to percentage of carbon in the compound?
how to find sigma and pi bonds and what are they?

 

[SohaibButt]

Someone pls help it's ans is B y not D?