I NEED HELP PLZZZZZZZZZZZZZZZZZZZZZZzz?

Question

procedure:
1. add a small sample of NaCI to 5 ml of water in a t.t shake the content of the tube

2. using a dropper, add 5 drops of silver nitrate to the salt water solution

3. obtain a 2cm piece of Mg RIBBON, ROLL IT UP AND PLACE IN A T.T. ADD ADDITIONAL HCI untill all of the mg ribbon is gone.



can you tell me observation and physical, chemical changes

Answer 1

Part 2 will yield a white precipitate of silver chloride. Most chlorides are soluble, but silver is an exception.

Part 3: hydrogen gas will bubble off, as the magnesium oxidizes and goes into solution. The resulting product is magnesium chloride, which when dried will be a white salt.

Answer 2

Right, . . .


After dissolving the salt into the water, you place a few drops of Ag(NO3)2 into the water. Immediately you will note a cloudy white precipitate, sort of milky looking. This is Silver Chloride. Silver Chloride Ag(Cl)2 is a white powder when dry. Using Silver nitrate solution is a very sensitive and clasic, test for Chloride ions.

Sodium Chloride dis-associates into NA+ and CL- in to the polar water H2O. The Silver Nitrate, AgNO3 is already disolved in the water and has dis-associated as AG+2 (NO3.)-2
The ions interact, and the least soluble combination will precipitate out of solution.
If you check solubility charts, you will find that Silver Chloride is nearly insoluble in water, and that will precipitate out as a cloudy white precipitate. If any Chloride is present, when you add the silver nitrate, you will see cloudy white precipitate.
By the way, When you first placed the sodium chloride NaCl white crystals ( common table salt), into the test tube with the water, it dissoved very quickly.

Magnesium:
When you place metalic Magnesium into water, or water with some Hydrochloric acid ( to speed things up considerable), you will notice bubbles forming around the metal, and rising to the surface. The bubbles are Hydrogen gas, produced by the Magnesium donating electrons to the Oxygen from the water.
The reaction produces Magnesium Oxide, which is a white milky substance, and will look similar to the first reaction above.
( dry Magnesium oxide is a white powder ).
The test tube may get a little warm if the acid is concentrated, and the reaction progresses quickly. If you light a wooden splint, and place it at the top of the test tube ( use safety glases), the hydrogen will explode with a disturbing "pop". The space shuttle main engine uses liquified Hydrogen and Oxygen to lift the vehicle into orbit, that is what is in the large external fuel tank.

Water is formed by Oxygen and Hydrogen H2O. The Oxygen having 6 valence electrons, and needs 2 more, to complete its Octet ( see octet rule). Hydrogen ( electropositive) has one electron, and usually lets Oxygen have it most of the time. Oxygen is very electronegative ( Electronegative atoms are close to the upper right side of the periodic table). Electronegative atoms are closer to filling their shells, to get 8 electrons in their outer most shell. Flourine is the most electronegative element, because it is in the 7th ( of 8) group. It has 7 electrons, and wants one more to complete its shell, and have the configuration of the elements in the 8th group ( the Nobel gases Ne, Ar etc.). Nobel gases dont react with any other chemicals or atoms, because they already have their shells filled, and dont need to bond with anything else.

Electropositive:
Hydrogen on the other hand, and Magnesium, are electro-positive. They are on the left side of the periodic chart on the lower left.
They have filled their previous shell, and have started to fill the next shell. But they only have one or two electrons, and will need 6 or 7 more to fill the shell. It will release energy for them to just give up those electrons, and fall back to their previously filled shell configuration like the nobel gases. So they are actually willing to give up electrons, and will donate energy to do it. Here have my electron please ! Where as electrnegative atoms are desparate to get an electron and like bullys, and will steal it from any unsuspecting atom or molecule, particularly Flourine. Dont mess with Texas, .. I mean Flourine.

So Hydrogen, goes out of its way to donate its electron to Oxygen, who needs two. Thats why water is H2O. Oxygen needs two Hydrogen atoms, actually needs two electrons.

The Magnesium MG+2 has two electrons, and lower down and sort of left on the chart, so it is electro positive.
The Magnesium is more electropositive than Hydrogen, and the magnesium kicks off the two hydrogens, and is even happier to donate its two electrons to Oxygen who just happens to need two electrons. MgO. A white precipitate.


May the force be with you..

Austin Semiconductor

Answer 3

this sounds like a project that you should have done instead of going to the mall, movies the local hangout (pick one).
me thinks you are going to get a big "f" for not doing this simple project that would have taken no more than half an hour to complete. time to get your priorities together.