- At ALL TIMES you will wear chemical splash goggles.
- We will dispose of materials properly, see me.
- We will wash hands thoroughly when done.
We will be dealing with the following TOXIC CHEMICALS:
We will be dealing with the following SKIN IRRITANTS:
Silver Nitrate and Iodine will stain your skin and clothing.
It is easy to get chemical PROPERTY confused with chemical CHANGE... the act of dissolving is a physical change, because the solute is not chemically altered.
A physical property is any property that is measurable and whose value describes a state of physical matter. Physical properties are often referred to as observables.
Simply speaking, chemical properties cannot be determined just by viewing or touching the substance; the substance's internal structure must be affected for its chemical properties to be investigated; i.e. a chemical reaction must take place.
For those of you wondering what is going on...
What does melting point tell us?
This is a PHYSICAL PROPERTY.
The melting point of a solid is the temperature at which it changes state from solid to liquid.
What does solubility tell us?
This is a PHYSICAL PROPERTY. All the rest are chemical reactions/properties.
This is another property of a chemical.
What does the reaction with HCl tell us?
HCl is Hydrochloric acid and it is formed with the combination of Hydrogen and Chlorine gases. It will react with nearly all Alkali metals and bases as it is a strong acid.
What does the reaction with Silver Nitrate tell us?
Silver Nitrate will react with metals and hallides (Cl, I, Br, etc.)
Why do we mix it with Sodium Carbonate?
We are looking for a reaction. If a reaction takes place, you should see a salt form (precipitate).
What does the reaction with Iodine tell us?
There are a lot of things that react with Iodine. Group one (the Alkali metals) react the most commonly....for example if you combine Potassium (K) you get Potassium Iodide (KI).
Also, the Iodine test is used to test for the presence of starch. Iodine solution — iodine dissolved in an aqueous solution of potassium iodide — reacts with the starch producing a purple, black color.
Other reactions involve more of a reddish-brown color change.