Answer:
The correct answer is:
<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>
Explanation:
The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.
Answer:
Mass = 9.58 g
Explanation:
Given data:
Mass of Zn = 2g
Theoretical yield of ZnI₂ = ?
Solution:
Chemical equation:
Zn + I₂ → ZnI₂
Number of moles of Zn:
Number of moles = mass/molar mass
Number of moles = 2g / 65.38 g/mol
Number of moles = 0.03 mol
Now we will compare the moles of Zn and ZnI₂.
Zn : ZnI₂
1 : 1
0.03 : 0.03
Mass of ZnI₂:
Mass = number of moles × molar mass
Mass = 0.03 mol × 319.22 g/mol
Mass = 9.58 g
Answer:
Odour is intensive
Explanation:
intensive properties are Independent of the amount of matter
Answer:
The average pressure in the container due to these 75 gas molecules is 
Explanation:
Here Pressure in a container is given as

Here
- P is the pressure which is to be calculated
- ρ is the density of the gas which is to be calculated as below

Here
mass is to be calculated for 75 gas phase molecules as

Volume of container is 0.5 lts
So density is given as

is the mean squared velocity which is given as

Here RMS is the Root Mean Square speed given as 605 m/s so

Substituting the values in the equation and solving

So the average pressure in the container due to these 75 gas molecules is 