this is the procedure. help me answer the these questions Taken from: Laboratory

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this is the procedure. help me answer the these questions

Taken from: Laboratory Experiments: Chemistry The Central Science, Twelfth Edition Experiment 8 Chemical Reactions To observe typical chemical reactions, identify some of the products and OBJECTIVE summarize the chemical changes in terms of balanced chemical equations. Apparatus Bunsen burner and hose 6 in. test tube thistle tube or long-stem funnel droppers (2) APPARATUS AND CHEMICALS crucible and cover glass tubing ring stand, ring, wire triangle Chemicals 0.1 M sodium oxalate, Na2C204 10 MNaOH powdered sulfur 0.1 M KMn0 0.1 M Pb(NO)2 6 MHCI 6 M H2SO4 mossy zinc 6 M NH3 (ag) conc. HNO 3 M (NH4)2CO 0.1 M NaHSO, (freshly prepared) KMno, 2 in. length of copper wire 2 1 in. lengths of copper wire (14-, 16-, or 18- gauge) a2CO Na2SO ZnS 0.1 M BaCl2 Chemical equations represent what transpires in a chemical reaction For exam-DISCUSSION ple the equation 2KCIo,(s)-A2KCI)+302(8) means that potassium chlorate, KClO,, decomposes upon heating (? ?s the symbol used for heat) to yield potassium chloride, KCl, and oxygen, O2. Before an equation can be written for a reaction, someone must establish what the products are. How does that person decide what these products are? Products are identified by their chemical and physical properties as well as by analyses. That oxygen rather than chlorine gas is produced in the above reaction can be established by the fact that oxygen is a colorless, odorless gas. Chlorine, on the other hand, is a pale yellow-green gas with an irritating odor. In this experiment, you will observe that in some cases, gases are produced, precipitates are formed, or color changes occur during the reactions. These are all indications that a chemical reaction has occurred. To identify some of the products of the reactions, consult Table 8.1, which lists some of the properties of the substances that can be formed in these reactions. Reagent bottle may be labeled 6 MNHOH

Explanation / Answer

At a time maximum 4 questions is answered so answer of first four question are as follows:-

1. An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. Two compund tested that are storng oxidising agent are KMnO4 and K2CrO4

2. Zinc reacts quickly with the acid to form bubbles of hydrogen as the hydrogen reacts with oxygen to form water.
The zinc metal begins the process as a pure metal with an ionic charge of zero and loses an electron as it reacts with the acid to become a positively charged zinc ion through oxidation. At the same time, hydrogen undergoes reduction by gaining an electron to become a neutral molecule and zinc chloride is formed.

Zn + 2HCL ----> ZnCl2 + H2

3. No reactions occurs and copper being as inactive metal. It is considered as unreactive metal because Copper has electron configuration [Ar] 3d10 4s1 while zinc has [Ar] 3d10 4s2.In aqueous solution, metals generally form positive ions by losing their outer electrons.Here the outermost electrons are in the 4s orbital for both zinc and copper, but Zn has two electrons in the 4s while Cu only has one. So zinc easily forms a 2+ ion in solution and copper can't displace Zn2+ in solution because to lose two electrons it would be necessary to break up the closed 3d sub-shell. Even though Cu has a smaller nuclear charge this is not enough to compensate for breaking up the d-shell, which gains a little stability due to being completely filled.

4.After reaction solution turns green and brown orange gas is liberated. Nitric acid is an oxidizing agent and the reaction is not the usual acid + metal reaction. The products are oxides of nitrogen instead of hydrogen. The actual nitrogen oxide formed depends on the concentration and temperature of the acid.

Cu+4HNO3?Cu(NO3)2+2NO2+2H2O

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