Reactions in Real Life- Lab 5B

It's easy to find products of reactions on paper, but it's much more difficult to identify substances when doing experiments.  This is why learning to balance equations is so important!

These are some of the things to keep in mind:

Indicators of chemical changes:

colour change

-hydrate loses water molecules and becomes an anhydrous salt

bubbles
-bubbles rise to the surface as gases are released

heat or light

-as you can see there is steam and condensation on the sides of the test tube, signalling that the reaction released heat

formation of a precipitate

-a solid forms and settles on the bottom of the test tube

Some reactions like combustion react with the elements in air or water.  There are several ways of testing the identity of the substance.  If it is a gas, you could light a splint and put it into the test tube to see if it ignites.  You could also find the mass of 1 mole of the substance( 1 mole = 22.4 L at STP)

Watch these video.

http://www.youtube.com/watch?v=0y9NOyTgJ88&feature=related

Write a balanced chemical equation for the reaction.

What did the person do to confirm the identity of the gas being released?(O2)

http://www.youtube.com/watch?v=mtjbg6ZF5K4

The two reactants are hydrogen peroxide(H2O2) and potassium iodide.  Predict the two products. 
What type of reaction is this?

What evidence is there that a chemical change has occurred?