Answer:

Explanation:
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In this case, when looking over the chemical formula of a compound formed when two elements interact, we need to realize about their location in the periodic table; thus, since lithium is a metal and oxygen a nonmetal, we infer lithium turns out the cation and oxygen the anion. Moreover, as the oxidation state of lithium is 1+ and that of oxygen is 2-, we can set up the chemical formula as follows:

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We know that Weighted atomic mass of Element is Calculated based upon their existence of isotopes and the Relative abundance of these isotopes.
Given that the Element X is Composed of :
Isotope Relative abundance Atomic Mass
⁵⁵X 70% 55
⁵⁶X 20% 56
⁵⁷X 10% 57
Weighted Atomic Mass of Element X :
= (0.70)(55) + (0.20)(56) + (0.10)(57)
= 38.50 + 11.2 + 5.70
= 55.4
So, the Weighted Atomic Mass of Element X is 55.4
it will be hard, but you can do it. Just study given the materials for the course. Understand enthalpy and entropy, and various types of bonding and you'll be fine.
The formula for kinetic energy is KE=1/2(mv²). Since both mass and velocity are multiplied by each other, particle with a larger mass needs to be moving slower than a particle with less mass if both have the same kinetic energy. You can think of it as 2KE/m=v² or 2KE/v²=m, If you increase the mass the velocity needs to decrease to keep the same KE value.
I hope this helps. Let me know in the comments if anything is unclear.
The dichloromethane (DCM) has less density than water and also the polarity of water is much more than DCM. So the mixture of water and dichloromethane will always be a heterogeneous mixture. In the mixture dichloromethane will be always up of the water layer. The volume of the separatory funnel which contains the mixture of DCM and water must have to be more than the total volume of the liquids thus the volume of the funnel will be more than (50+50) = 100mL.
The caution have to consider during the separation are-
1. The separatory funnel have to shake well with lid and have to settle down for some times until the two liquid separated.
2. The lid should be open very slowly as the vapor pressure of DCM is more and it will float on the water.
3. After this the stopcock should be opened and slowly the water will come out first followed by DCM.