Answer:
Explanation:
This question seeks to test the knowledge of separation techniques.
From the narration in the question, the first separation to be done is the removal of Iron fillings by the use of magnet (magnetic separation). Since Iron is magnetic, the iron fillings will be attracted by the magnet hence removing the iron fillings from the mixture.
The second constituent to be removed will be the copper pieces by the use of a sieve (sieving). Copper pieces have relatively larger sizes than sand and common salt, hence a sieve (which separates particles based on size) can be used to remove the copper pieces from the mixture.
What will be left in the mixture after the processes above will be salt and water. This mixture will have to be dissolved in water; the salt will dissolve in water while the sand will not. After which, filtration will be done to remove the sand which will be collected on the filter paper as filtride and the salt solution will pass through the filter paper as filtrate.
The salt solution can then be evaporated to dryness to retrieve the solid salt from the solution.
The amount of salt in the mixture can then be measured using a weighing balance.
Some of safety measures to be taken during the course of this experiment includes performing the experiment in an airtight and controlled environment. Lab coat and hand gloves should be worn during the course of the experiment. The evaporation to dryness should not be done close to an inflammable material/substance
I believe that the answer is molecule
Explanation:
The charge of an ion would be +2
Answer :
1.) 
Calcium has 2 valence electrons and chlorine has 7 valence electrons. For neutral molecule, 2 chlorine atoms share their valence electrons with 1 calcium atom. The bonds are formed between the calcium and chlorine atom.
2.) 
Aluminium has 3 valence electrons and fluorine has 7 valence electrons. For neutral molecule, 3 fluorine atoms share their valence electrons with 1 aluminium atom. The bonds are formed between the aluminium and fluorine atom.
3.) 
Hydrogen has 1 valence electron and chlorine has 7 valence electrons. For neutral molecule, 1 chlorine atom share their valence electrons with 1 hydrogen atom. The bonds are formed between the hydrogen and chlorine atom.
4.) 
Hydrogen has 1 valence electron and sulfur has 6 valence electrons. For neutral molecule, 2 hydrogen atoms share their valence electrons with 1 sulfur atom. The bonds are formed between the hydrogen and sulfur atom.
5.) 
Chlorine has 7 valence electrons. For neutral molecule, 1 chlorine atom share their valence electrons with 1 chlorine atom. The bonds are formed between chlorine and chlorine atom.
The lewis-dot structure image is shown below.
