Answer:
If a saturated hot solution is allowed to cool, the solute is no longer soluble in the solvent and forms crystals of pure compound. Impurities are excluded from the growing crystals and the pure solid crystals can be separated from the dissolved impurities by filtration.
The difference between a mixture and a compound is that a mixture can be easily separated like a salad where you can pick things out and a compounds you are usually not able to undo
The integrated rate law expression for a first order reaction is
![ln\frac{[A_{0}]}{[A_{t}]}=kt](https://tex.z-dn.net/?f=ln%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D%3Dkt)
where
[A0]=100
[At]=6.25
[6.25% of 100 = 6.25]
k = 9.60X10⁻³s⁻¹
Putting values

taking log of 100/6.25
100/6.25 = 16
ln(16) = 2.7726
Time = 2.7726 / 0.0096 = 288.81 seconds
The basic substances are called elements