Answer:
Explanation:
Endothermic reactions absorb energy from the surrounding, but exothermic reactions release energy to the surrounding.
To determine the upper bond
Ec(u) = EmVm + EpVp
Em is the elastic modulus of cobalt.
E₁ is the elastic modulus of the particulate
Vm is the volume fraction of cobalt
Vp is the volume fraction of particulate
substitute
Ec(u) = 200 (Vm) + 700 (Vp)
To determine the lower bound
Ec (l) = EmEp/VmEp+ VpEm
Substitute
Ec (l) = 200(700)/Vm(700) + Vp (200)
Ec (l) = 1400/7Vm+2Vp
Answer:
Explanation:
Calcium chloride is <u>deliquescent.</u> If exposed to air, it will absorb sufficient water from the air to allow it to dissolve. After a short while, instead of a white lump, you will have a pool of clear liquid.
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.
