Answer:
(C) The recrystallization solvent should be nonvolatile.
Explanation:
Recrystallization is the separation technique which is used to purify the solid compounds in their crystal or amorphous form.
Some properties follow the recrystallization process as:
The solids are more soluble in hot solvent as compared to the solubility in the cold solvent.
The solvent must have lower boiling point and can be volatile easily.
The solvent should not react with the compound.
The impurities must be soluble in the cool solvent, so that only the pure product crystallizes.
Hence, Answer - C which is not an ideal characteristic.
In this reaction 50% of the compound decompose in 10.5 min thus, it is half life of the reaction and denoted by symbol
.
(a) For first order reaction, rate constant and half life time are related to each other as follows:
![k=\frac{0.6932}{t_{1/2}}=\frac{0.6932}{10.5 min}=0.066 min^{-1}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B0.6932%7D%7Bt_%7B1%2F2%7D%7D%3D%5Cfrac%7B0.6932%7D%7B10.5%20min%7D%3D0.066%20min%5E%7B-1%7D)
Thus, rate constant of the reaction is
.
(b) Rate equation for first order reaction is as follows:
![k=\frac{2.303}{t_{1/2}}log\frac{[A_{0}]}{[A_{t}]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt_%7B1%2F2%7D%7Dlog%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D)
now, 75% of the compound is decomposed, if initial concentration
is 100 then concentration at time t
will be 100-75=25.
Putting the values,
![0.066 min^{-1}=\frac{2.303}{t}log\frac{100}{25}=\frac{2.303}{t}(0.6020)](https://tex.z-dn.net/?f=0.066%20min%5E%7B-1%7D%3D%5Cfrac%7B2.303%7D%7Bt%7Dlog%5Cfrac%7B100%7D%7B25%7D%3D%5Cfrac%7B2.303%7D%7Bt%7D%280.6020%29)
On rearranging,
![t=\frac{2.303\times 0.6020}{0.066 min^{-1}}=21 min](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B2.303%5Ctimes%200.6020%7D%7B0.066%20min%5E%7B-1%7D%7D%3D21%20min)
Thus, time required for 75% decomposition is 21 min.
a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
- a person or thing that precipitates an event.
Answer:
Magnetism is believed to be caused by the alignment of small, numerous sub-units called : <em><u>Domains</u></em>
<em><u></u></em>
Explanation:
Domains : A magnetic domain is the region in which in which magnetic field of the atoms are grouped together and aligned.
- In unmagnetized material all the magnetic Domains point in different direction.
- In magnetised material (ferromagnets , antiferromagnets) , The Domains point in a particular( fixed Pattern) direction.
I think its chlorine Im not positive but im 99.9 precent shure