HELP ! DUE TOMORROW MORNING !

[serrah]

1) Why should the electrical conductivity of the deionized water be tested before testing the conductivity of the solution ?
2) Can a substance be classified as ionic or molecular based only on its soulbility in water ? Explain.
3) Can a substance be classified as ionic or molecular based only on the color of its solution.Explain.
4) Can a substance be classified as ionic or molecular based only on its phase at room tempature ? Explain.
5) Can a substance be classified as ionic or molecular based only on the electrical conductivity of its solution ? Explain.


p.s: I know that its really too late to start this but if you could help me with the answers that would be AMAZINGGGGG

[davidkallman]

Hi serrah,

Welcome to the bulletin board!

One way to get answers to your questions is to submit each of your five questions to answers.com A good hit usually shows up early in the output.

I know the method above requires work on your part and won't fit into your schedule. I'll be able to do more work on this on Tuesday, but won't since it's past your schedule. Maybe someone else can help.

[Craig_Bridge]

1) Why should the electrical conductivity of the deionized water be tested before testing the conductivity of the solution ?

This will validate (or invalidate) your test setup. By testing what you think is a known, you will be able to detect if there is a contaiminant or error in your setup.

Can a substance be classified as ionic or molecular based only on ...

This sounds more like a chemistry homework problem than something related to a science fair project. The chemical formula for the substance and the solvent is the best predictor for whether the substance will likely stay bound together as a molecule or if it will break apart into ion pairs. The change in the electrical conductivity between a solvent and a solution based on that solvent and the substance is a good indicator of whether ionization has occurred; however, the lack of a change does not necessarily mean that ionization has not occurred. There can be some oxidation / reduction reactions at the electrodes that will produce insulators which will prevent current flow at a given potential. There are also substances where there is a danger of causing an electro-chemical reaction that releases poisonous gases such as chlorine. In order for any of the methods listed to be confirmation of ionization or lack thereof, you have to know what the possible chemical reactions are and use those indications to confirm or disprove that the hypothetical reaction occured or not.