The picture below gives the appearance of a halide sodium chloride and water and hexane. Wipe the lab table thoroughly with a wet sponge or paper towels. Aluminum is the reducing agent, and chlorine is the oxidizing agent. You will do this by reacting each of the halogens with each of the aqueous halides and with solid copper. Manganese is the substance reduced, and bromine is the substance oxidized. Its necessities include the right temperature, amounts of water, season, surrounding air, amount of sunlight, and soil conditions.
Net Ionic Equations for Halogen Reactions 2Cl- aq + Br2 aq Cl2 aq + 2Br- aq 2Br- aq + Cl2 aq Br2 aq + 2Cl- aq 2Br- aq + I2 aq Br2 aq + 2I- aq 2I- aq + Cl2 aq I2 aq + 2Cl- aq 2I- aq + Br2 aq I2 aq + 2Br- aq The list in decreasing order of reactivity is Cl, Br, I. Dispose of the four test tubes by placing them in the recycling bin. Observe and record any evidence of a reaction with each of the four halogen ions in your Lab Notes. Remember that just because a color appears it does not mean that a reaction has occurred. Note, you will be balancing redox reactions using the half-reaction method in this lab and reporting any reactions that occur in lab in their final balanced net ionic reaction.
It actually takes less energy to remove an electron from a fluoride ion than from a chloride ion. Use adequate ventilation when working with either bleach or ammonia. Qualitative Analysis to determine if a reaction has occurred A chemical reaction may be analyzed quantitatively or qualitatively. One should not expect the halide ions to dissolve in mineral oil because the ions are polar whereas the mineral oil is nonpolar. The activity series can be used to predict products of reactions, and to predict if a reaction will even occur. . Remember, water is a very polar solvent, and hexane is very non-polar.
. When a halogen and halide from different elements are combined, i. Spectator Ions and Net Ionic Equations Many ionic compounds dissociate in water to form solvated ions, as can be seen in Common Ion Chart found in the Week 1 Moles Galore Lab. The table above shows that this has nothing to do with the amount of energy required to remove an electron from a fluoride ion. Testable Question: What will happen to different halide salts found in the body if various compounds are added to the halide? Sodium chloride is important for many life processes, but too much intake is linked to high blood pressure.
Hint they are in air, one is what air is mostly made up of, and the other is required for us to breath When the diatomic halogens react, they gain an electron and become individual negatively charged ions or anions. Introduction Reactions may or may not occur between two elements based on the activity series. None of the halides formed a precipitate Question 15. Use adequate ventilation when working with either bleach or ammonia. Potassium K , Calcium Ca Magnesium Mg , and Sodium Na. In qualitative analysis, changes in a reaction mixture are observed and that information is used to determine whether or not a reaction occurred. Based on the appearance, you can visually see if a reaction has occured between the two species.
Note which chemical species is being oxidized and which is being reduced. When used as a photography-oriented activity, this is an excellent applied chemistry activity. The results of the lab do not agree with prediction because the periodic property of electronegativity is that it decreases in a group as atomic number increases. In the lab you will conduct redox experiments and determine which pairs of oxidizing agents and reducing agents will react in a given set. In the process, bromide ions are oxidized to bromine. This jar should contain a large amount of water. This was a key observation for calcium to be placed at the top of the activity series, because it was able to react with magnesium, zinc, iron, tin, and copper ions.
Create a table similar to Table 2 below. Use the second digit of the unknown number as the key. In this experiment, different metals were tested for their reactivity. Figure 1: Trends in bonding atomic radii for periods 1-5 Ref: Brown et. There are two important reasons why fluoride ions are so difficult to oxidize.
Shake and record the color produced when the halogen is dissolved for each test tube. Answer whether there was a reaction or not in the following combinations. Notice that each of the halogens are colored. If so, make sure to head to the front bench to make observations of these reactions. Observe and record any evidence of change. The Oxidizing agent is a chemical species that causes the electron to leave, and draws in the electron to itself.
Write the balanced net ionic chemical equation for each reaction that occurred. Observe and record any evidence of change. Therefore, we need to find a way to differentiate the halogens in the reaction in order to determine if a reaction as occurred or not. The diagram shows that the overall change involving the halide ions is endothermic the green arrow is pointing up toward a higher energy. Silver solutions cause black stains on skin.