Question

Classifying Reactions Lab Help!

Answer 1

1. The reaction between iron and oxygen is 2Fe + 1.5O2 → Fe2O3
2. The reaction is combination.

1. The reaction between zinc and acetic acid is 
2Zn + 2C2H4O2 → 2Zn(CH3COO)2 + H2
2. The reaction between zinc and acetic acid is double displacement.
3. The evidence that a reaction was taking place is the presence of bubbles.

Answer 2

Answer 1) Part I (Day 1) Steel wool and vinegar experiment;

The complete balanced reaction between iron and oxygen is

$4Fe + 3O_{2} ---> 2Fe_{2}O_{3}$

Explanation : The reaction which occurred between iron and oxygen was the oxidation and reduction reaction where iron got oxidized and oxygen got reduced. The steel wool when placed in vinegar removed the upper coating on it; And when it was dipped in water the reaction began.

Answer 2) The reaction was redox (oxidation commonly for iron).

Explanation : Mainly oxidation of iron was observed as the formation of rust was the reaction product that was seen. The iron layer on the steel wool got exposed with water in presence of oxygen which developed a slight greenish or brownish layer on the surface of steel wool indicating formation of rust.

Answer 3) The evidence seen for this reaction was formation of rust on steel wool
.

Explanation : When the soaked steel wool from the vinegar was removed, the protective coating of the steel wool was removed. Which allowed the iron in the steel to form rust. Also, rusting created heat energy which increased the temperature inside the beaker
. These were the evidences that the reaction took place.

Answer 4) Part
II Reaction of Hydrogen Peroxide

1) The complete balanced chemical reaction is $2H_{2}O_{2}--->2H_{2}O + O_{2}$

Explanation :
The potato (as well as yeast and beef liver) which contains an enzyme called catalase, was broken down by hydrogen peroxide. The molecules of hydrogen peroxide when broke down produced water and oxygen as the products.

Answer 5) 2) This was an example of decomposition reaction
.

Explanation : It was clear from the reaction that the molecules of hydrogen peroxide are undergoing decomposition; as it got broken down into molecules of water and oxygen. This breaking of hydrogen peroxide is an example for decomposition reaction.

Answer 6) 3) Oxygen bubbles escaped and foam was formed
.

Explanation : A damaged enzyme may not be able to catalyze a chemical reaction. So, catalase the enzyme present in the liver helped to break down harmful hydrogen peroxide into oxygen and water. When this reaction occurred, oxygen gas bubbles were seen to get escaped and created a foam.

Answer 7) Part
III Zinc and acetic acid reaction

The complete balanced reaction is $Zn + 2CH_{3}COOH ---> Zn(CH_{3}COO)_{2} + H_{2}$.

Explanation : Zinc reacted with the acetic acid solution and produced zinc acetate as the product. This copper penny when rubbed with sandpaper removes the outer covering of copper and exposes zinc with acetic acid so that the reaction occurs.

Answer 8) 2) This is a single displacement
reaction.

Explanation : Zinc is more reactive and it displaced the active hydrogen from the acetic acid; which is given out in the form of hydrogen gas. The formation of zinc acetate confirms the occurrence of the single displacement reaction.

Answer 9) 3) Appearance of Hydrogen bubbles.

Explanation : The evidence that showed that reaction was taking place is the presence of hydrogen bubbles. When the zinc penny was exposed to acetic acid it reacted with it. Which gave out hydrogen gas as a byproduct in the form of bubbles in the solution. This confirms the evidence that reaction was occurring.

Answer 10) Part IV Magnesium sulfate and ammonium hydroxide reaction.

The complete balanced reaction is $MgSO_{4} + 2NH_{4}OH ----> (NH_{4})_{2}SO_{4} + Mg(OH)_{2}$.

Explanation : When magnesium sulfate reacts with ammonium hydroxide it forms ammonium sulfate and magnesium hydroxide as the products. The product was obtained in a precipitate form.

Answer 11) 2) This was a double displacement or it can be said as precipitate
reaction.

Explanation : It can be said as a double displacement reaction because the magnesium and ammonium ions were displaced and a new product was formed. The anions and cations exchanged in their molecules and produced new molecules. It can also be called as precipitate reaction as there was a precipitate obtained after the reaction.

Answer 12) 3) Cloudiness in the chemical reaction
.

Explanation : When the Epsom salts which contained magnesium sulfate and ammonia in ammonium hydroxide reacted, there was no changes seen. After sometime, when the reaction was allowed to settled the solution appeared to be cloudy. The precipitate was not formed quickly but it took time for the formation.