Synthesis, Decomposition, Single Replacement and Double by pptfiles

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Synthesis, Decomposition, Single Replacement and Double Replacement Reactions Name_____________________
Date__________ Period______
C.S.C.S. 3, b, f; 5, a, b, c; 7, c; 9, a, b

A. Synthesis Reactions: The word synthesis means, “to put together”. In a chemical reaction involving synthesis, two or more substances combine to produce a single, more complex substance. Activity: Observe a Synthesis Reaction Observe the magnesium metal and record 2 physical properties of it below. Watch the teacher burn the magnesium metal in air. Observe the magnesium metal after the heating and record 2 physical properties of it below. Physical Properties Magnesium before heating Magnesium after heating Questions: 1. What is the evidence that a chemical change occurred? ________________________ _____________________________________________________________________ 2. How many products are in a synthesis reaction? _____________________________ 3. Oxygen was one of the reactants in this reaction. Where did the oxygen come from? _____________________________________________________________________ 4. Is this product of a synthesis reaction an element or a compound? _______________

B. Decomposition Reactions: Chemical decomposition is the opposite of chemical synthesis. In a decomposition reaction, a single compound is broken down into two or more simpler substances. Some compounds can decompose by themselves. Since hydrogen peroxide, for example, decomposes over time to form water and oxygen at room temperature, expiration dates are stamped on the bottles. In many cases heat, light or electricity is required to decompose compounds. Activity: Observe a Decomposition Reaction Observe the sugar and record 2 physical properties of it below. Watch the teacher heat the sugar. Observe and describe the sugar after it has been heated. Description Sugar before being heated Sugar after being heated

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Questions: 1. What evidence do you have that a chemical change took place? _________________ _____________________________________________________________________ 2. How many reactants are in a decomposition reaction? _________________________ 3. What was necessary for this reaction to take place? ___________________________

C. Single Replacement Reactions: In a single replacement reaction, an uncombined element replaces an element that is combined in a compound. This rearrangement of atoms causes a new compound and element to be formed. Activity: Observe 2 Single Replacement Reactions Part A: (optional) a. Rinse out the graduated cylinder. Measure 5 ml of copper sulfate (CuSO4) and pour it into a test tube. b. Observe the iron nail and the copper sulfate and record their colors in the data table below. c. Drop the nail into the solution and observe the nail and the solution. Let the nail sit in the solution over night. You will observe it tomorrow. Color Iron nail (before put into solution) Copper sulfate solution (before nail is added) Iron nail (after being in solution) Copper sulfate solution (after nail has been added) Part B: d. Rinse out the graduated cylinder. Measure 2 ml of silver nitrate (AgNO3) and pour it into a test tube. e. Observe the copper nail and the silver nitrate and record their color in the data table. f. Drop the nail into the solution and observe the nail. Keep the test tube as steady as possible. This reaction happens immediately, be sure to watch carefully!!!! g. After the reaction has taken place, shake the “fuzz” off the nail and the reaction will happen again. h. Observe the color of the solution and record its new color. Color Copper nail (before put into solution) Silver nitrate (before nail is added) Copper nail (after being in solution) Silver nitrate (after nail has been added)

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Questions: 1. When the iron nail was added to the copper sulfate the following single replacement reaction occurred:

Fe

+

CuSO4

FeSO4

+

Cu

What are the reactants? ________________________________________ What are the products? ________________________________________ 2. What was your evidence that copper was a product of the reaction? ______________ _____________________________________________________________________ 3. When the copper nail was added to the silver nitrate the following single replacement reaction occurred:

Cu +

AgNO3

Cu(NO3)2 +

Ag

What are the reactants? ________________________________________ What are the products? ________________________________________ 4. What was your evidence that silver was a product of the reactions? _______________ _____________________________________________________________________

D. Double Replacement Reactions: Some of the most impressive chemical reactions are double replacement reactions. In double replacement reactions, there are two compounds as the reactants. The negative ions of each compound switch places with each other resulting in two new compounds. Activity: a. b. c. d. e. f. Observe 2 Double Replacement Reactions

Observe the LiCl solution and record the color below. Observe the Pb(NO3) 2 solution and record the color below. Put 3 droppers of LiCl into a test tube. Add 3 droppers of Pb(NO3) 2 to the LiCl. Shake the test tube back and forth for 15 seconds. Record the results and then clean your test tube. Color

LiCl Pb(NO3) 2 Result of reaction: LiCl + Pb(NO3) 2 g. Observe the KI and record the color. h. Record the color of the Pb(NO3) 2.

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i. Put 1 dropper full of Pb(NO3) 2 into a clean test tube. j. Add 1 dropper full if KI to the lead nitrate and record the results. Color KI Pb(NO3) 2 Result of reaction: KI + Pb(NO3) 2 Questions: 1. The following is the equation for the 1st double replacement reaction you observed. Balance the equation:

Pb(NO3) 2

+

LiCl

PbCl2 +
(white solid)

LiNO3

2. The following is the equation for the 2nd double replacement reaction you observed. Balance the equation:

Pb(NO3) 2

+

KI

PbI2 +
(yellow solid)

KNO3

CONCLUSIONS OF TYPES OF REACTIONS LAB ACTIVITY
1. Name the 4 types of reactions. ___________________________________________ _____________________________________________________________________ 2. What is the difference between a synthesis reaction and a decomposition reaction? _____________________________________________________________________ _____________________________________________________________________ 3. In your words, describe what happens in a: a. Single replacement reaction ___________________________________________ _____________________________________________________________________ _____________________________________________________________________ b. Double replacement reaction __________________________________________ _____________________________________________________________________ _____________________________________________________________________ 4. When you take the cap off a bottle of soda, bubble rise quickly to the top. This is because carbonated beverages, such as soda, contain the compound carbonic acid (H2CO3). This compound breaks down into water and carbon dioxide gas. The

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carbon dioxide gas is what makes up the bubbles that are released. Below is the equation for this reaction:

H2CO3

H2O +

CO2

What type of reaction is this? ____________________________________________ 5. If you have ever had an upset stomach, you may have taken a medicine that contained the compound magnesium carbonate. This compound reacts with the hydrochloric acid in your stomach in the following way:

MgCO3

+

HCl

MgCl2

+

H2CO3

What type of reaction is this? ____________________________________________ The product H2CO3 is then decomposed into water (H2O) and carbon dioxide gas (CO2). Your stomach ache goes away because instead of too much acid in your stomach, there is now water and carbon dioxide. 6. Name the type of reaction for the following: a. H2O H2 + O2 b. NaOH + HCl HOH + NaCl c. K + Cl2 KCl d. Pb(NO3) 2 + K2CrO4 PbCrO4 + KNO3 e. KClO3 KCl + O2 f. Mg + HCl H2 + MgCl2 g. Al2O3 Al + O2 h. BaBr2 + K2SO4 KBr + BaSO4 i. C + H2 + O2 C2H6O j. CaCO3 CaO + CO2 ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ ________________________ ________________________

7. The reactants in a synthesis reaction are shown below. Write in the products of the reaction.

Na

+

Cl2

8. The reactant of a decomposition reaction is shown below. Write in the products of the reaction.

CaS
9. The reactants of a single replacement reaction are shown below. Write in the products of the reaction.

Fe

+

CuCl2

10. The reactants of a double replacement reaction are shown below. Write in the products of the reaction.

NaCl

+

AgNO3


								
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