Why Is Litmus Paper Is Used To Identify Metal Ions

Chemical Reactions and Identifications of Unknowns

Data Analysis

Name: _Gloria Smith_________________________________________

Please answer the following questions with complete sentences unless a fill in the blank is given.

Your answers must be typed. Do not plagiarize!

Identification Tests:

Flame tests are used to identify the __metal ions_ of a compound.

Litmus paper is used to identify acids and bases. What general rule can be followed when using Litmus paper?

If the red litmus paper reacts with a base the place of contact will turn blue. If the red litmus paper does not change color, then the solution is an acid. In contrast, if the blue litmus paper turns red when it comes in contact with a solution,

(i.e., what was the evidence of reaction?)

When the piece of magnesium come in contact with the flame, it ignited and emitted an intense bright white light. The light was so intense that it was painful to look at. Furthermore, after the metal was done burning the piece of magnesium changed color and consistency. Before the reaction it was a dull gray, malleable piece of metal. After the reaction it was white and brittle, like a burnt piece of paper. It no longer displayed its original qualities.

Since the magnesium reacted with oxygen to form MgO, the mass of MgO should be greater than that of the magnesium. Did this occur? If not, why?

No, this result did not occur. The original mass of the magnesium was 0.07g, after the reaction the mass of the MgO was only 0.01g. Instead of gaining mass, the reaction resulted in a loss of mass. These results could be explained by the reaction itself. When the piece of magnesium ignited, minute particles were being expelled from the piece of metal. Evidence of such loss of material was displayed as a white film on the end of the tongs which held the metal. If the reaction was conducted in a more controlled environment, then maybe the theoretical results would be

When the students placed the wire containing the sample in the flame it burned a orange/ red color. when this result was compared with the previous flame tests it could have resulted from either CaCl2 or NaCl. Both of these compounds produced an orange flame. After the flame test was conducted, the students performed a litmus test to identify whether the unknown was neutral or a base. When exposed to the red and blue litmus paper, no reaction occurred. each paper remained it's original color, thus concluding that the unknown was neutral. These results also led the students to believe the unknown was CaCl2 since it was listed in the neutral column. After the litmus test was conducted the students added a few drops of Na3PO4 to the unknown. When these two were combined a precipitate was formed. This final test on unknown F verified that it was CaCl2. If it was NaCl there would have been no precipitate formed during this final