Classifcation of Chemical Reaction lab PDF

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LAGUARDIA COMMUNITY COLLEGE

SCC201 CHEMISTRY LABORATORY I LAB-CLASSIFIACTION OF CHEMICAL REACTIONS

Instructor: Professor Shakya

DISCUSSION 

A chemical reaction is any transformation of chemicals from one to another. The chemical reaction is any reaction in which transformation of the atoms occur and formation of new elements. We can use simple example to understand the chemical reaction 2 H 2( g) +O 2( g) →2 H 2 O ( l) Here in this example we can see chemical reaction between the hydrogen and oxygen occur and which result into formation of new substance water.

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Chemists represent their reaction by describing the type of the chemical reaction. They represent the elements and atoms in reaction by describing its state like solid, liquid, gas, and aqueous. They describe the catalyst, which need to use in the reaction. In short, chemist represent reaction in such a way that other can use that reaction to form that solutions.

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The five kind of reaction 1. Combination Two or more simple compound or elements combine to form a one product. A + B→ c Examples: S ( s )+ O2 (g)→ SO2 (g) Example from the experiment: Magnesium combine with oxygen to form magnesium oxide. 2 Mg ( s ) +O 2 → 2 MgO 2. Decomposition One reactant breaks down to form two or more simple compound or elements C → A +B Example: 2 KClO3 ( s ) → 2 KCl ( s )+3 O2 ( g ) Example from the experiment: Copper hydroxide is decomposed to form copper oxide and water Cu(OH )2 ( s ) → CuO(s)+ H 2 O (l) 3. Combustion Reaction of substance with oxygen (burning) If A is hydrocarbon in the reaction, A +O 2 ( g ) → CO2 +H 2 O ( g )

Example: C H 4 ( g ) +2 O 2( g ) →C O 2( g) +2 H 2 O (g) If A is meatal in the reaction, then metal oxide is form: 2 Mg ( s ) +O 2 → 2 MgO If A is nonmetal then nonmetal oxide is form: S ( s )+O 2 (g) → SO2 ( g) 4. Single Replacement: One element replaces the other elements during chemical reaction Example: Al ( s) +F e 2 O 3 ( s) +Fe ( s) Example from the experiment: Zinc metal react with copper sulfate and as a result zinc replace with the copper metal to form zinc sulfate. Zn( s) +CuS O4 ( aq )→ ZnS O 4( s) +Cu ( aq ) 5. Double replacement: This reaction occurs between ionic compound. Also, a reaction only occur if one of the new combination is insoluble, resulting in formation of a precipitate. AB+CD → AD +CB Example: Pb(N O3)2 ( aq) +2 Nal ( aq )→ Pb I 2( s )+ 2 NaN O3 (aq) Acid-base reaction (which yield salt and water) and the reaction of acid with carbohydrates and hydrogen (which yield salt, water, and carbon dioxide gas) are classified as double replacement reaction. Example from the experiment: 3 CaC l2 ( aq ) + 2 N a3 PO 4 ( aq ) →6 NaCl ( aq ) +Ca3 (PO 4)2 (aq)

Reactions and observations 1.

2 HCl ( aq )+Na2 CO 3 ( s) →2 NaCl ( s )+C O2 ( g )+H 2 O ( l ) Double Replacement Observation: No unique observation

2.

3 CaC l2 ( aq ) + 2 N a3 PO 4 ( aq ) →6 NaCl ( aq ) +Ca3 (PO 4)2 (aq) Double Replacement Observation: No unique observation

3.

Cu(OH )2 ( s ) → CuO(s)+ H 2 O (l) Decomposition reaction Observation: Black color powder is observed

4.

Zn( s) +CuS O4 ( aq )→ ZnS O 4( s) +Cu ( aq ) Single Replacement Observation: Zinc Metal become reddish brown

5.

Cu ( s )+ZnS O4 ( aq )→ CuS O4 (s )+ Zn ( aq ) Single Replacement Observation: No unique observation

6.

2 Mg ( s ) +O 2 ( g ) →2 MgO ( aq ) Combustion reaction Observation: Black light intensive color is observed

7.

HCl ( aq) + NaOH ( aq) → NaCl (aq ) + H 2 O( l ) Single Replacement Observation: No unique observation

8.

FeC l3 ( aq )+KSCN ( aq) → Fe ( SCN )3 ( aq) +3 KCl ( aq ) Double Replacement Observation: Reddish Black solution is observed

9.

2 Zn ( s ) +2 HCl (aq )→ ZnCl ( aq )+ H 2 (g ) Single Replacement Observation: Hydrogen gas produce and cracking sound heard

10.

Cu ( s )+2 HCl ( aq) →CuC l2 ( aq )+¿ Single Replacement Observation: No unique observation

11.

2 H 2 O 2 ( aq ) →2 H 2 O ( l) +O 2 ( g ) Decomposition reaction Observation: Stick do not blow off and white gas observed

12.

CuS O4 ( s)+5 H 2 O (l ) ← CuSO 4 ( s )× 5 H 2 O ( l ) Combination Reaction Observation: Blue color powder is seen

H 2 ( g)

→

13. NaCl ( aq) + KN O3 (aq ) → NaN O3( aq )+ KCl ( aq ) Double Replacement Observation: No unique observation...