Conclusion
The purposes of the single replacement lab conducted in class were: to write word and
complete chemical equations, to predict the products of the reactions and to identify an unknown
metal. The activity series helped to determine the predictions of the equations. The criteria for
making observations based on color changes in the aqueous solutions, the formation of a
precipitate and the production of a gas. The unknown metal was tin according to the reactions
that appeared based upon a general algebraic equation.
The general algebraic equation AX + B
BX + A determines if a reaction will occur
in a single replacement reaction. A reaction will not occur if B is less reactive than A since B is
trying to take A’s position in the compound. For example, Magnesium + Zinc Chloride produces
a reaction because magnesium is more reactive than zinc based on the Activity Series of Metals*,
so the chloride is more attracted to the magnesium. When the reciprocal is performed, Zinc +
Magnesium Chloride there is no reaction, since zinc is less reactive than magnesium.
In the equation of Iron + Magnesium Chloride, it produces no reaction. This was the
prediction as well as the observations of no color change, precipitate formation, or gas
production. Magnesium is higher on the Activity Series list, making Magnesium a more reactive
substance than Iron. This is why Iron would not be able to replace Magnesium.
However, adding Iron to Copper (II) Chloride forms the product of Iron (III) Chloride +
Copper. The predictions were correct, as Iron took Coppers place to bond with Chloride. As the
reaction took place, the Iron became an orange color, as the copper liquid had a color change
from turquoise to clear.
*
Activity Series of Metals: Lithium, Potassium, Calcium, Sodium, Magnesium, Aluminum, Manganese, Zinc,
Chromium, Iron, Lead, Tin, Hydrogen, Copper, Mercury, Silver, Platinum, Gold.
The Unknown metal is Tin. When experimented on, the unknown metal only slightly
reacted with copper chloride and hydrochloric acid. This gave us the information to know the
unknown metal was higher than hydrogen on the Activity Series of Metals. It was also observed
being that the unknown metal did not react with Iron. Therefore, the unknown metal had to be
between iron and hydrogen. It could have been either lead or tin. Although an experiment was
performed mixing lead with the unknown metal, it could still be lead, because mixing lead with
lead chloride would produce no reaction considering they are the same substance. The
conclusion of the unknown metal became tin because lead is dark gray based on prior
knowledge. The unknown metal was originally metallic silver. This brought on the final decision
of the unknown metal being tin.
In conclusion, no errors made with completing the purposes of the lab. The criteria shows
how aqueous solutions react with one another, to produce a precipitate, form a gas, or have a
distinctive color change. The Activity Series of Metals helped determine which single
replacement reactions will produce a reaction and which ones will have no reaction. At last, there
was an unknown metal to identify, which was tin, assuming our data was accurate.