Presentation on theme: "Posters 1.Signs of a chemical reaction 2.Chemical vs. Physical reaction 3.Symbols used in chemical reactions 4.Synthesis 5.Decomposition 6.Single diplacement."— Presentation transcript:
Posters 1.Signs of a chemical reaction 2.Chemical vs. Physical reaction 3.Symbols used in chemical reactions 4.Synthesis 5.Decomposition 6.Single diplacement 7.Double displacement 8.Combustion
Journal Entry How were these rocks formed?
Signs of a chemical reaction Production of…. Heat Light Gas Precipitate (solid formed from two liquids) Color change
5 The 5 Types of Reactions We classify reactions into 5 categories so that we may more easily predict the products. NEXT
Synthesis Definition Synthesis reaction – 2 substances are combined to form a single product Combination reactions may also be called composition or synthesis reactions. A + B AB + MENU
Synthesis Examples 2Mg + O 2 2MgO Magnesium and oxygen combine to form magnesium oxide. 2H 2 + O 2 2H 2 O Hydrogen and oxygen combine to form dihydrogen monoxide (water) MENU
Decomposition Definition Decomposition reaction – A single compound is broken down into 2 or more products. AB A + B + MENU
Decomposition Examples 2NaCl(s) 2Na(s) + Cl 2 (g) Sodium chloride (table salt) decomposes into sodium and chlorine gas. CaCO 3 CaO + CO 2 Limestone (CaCO 3 ) decomposes into lime (CaO) and carbon dioxide. MENU
Decomposition 2 H 2 O 2H 2 + O 2 Water decomposing into hydrogen gas and oxygen gas. Decomposition of H 2 O 2 MENU
Decomposition Demonstration C 12 H 22 O 11 + H 2 SO 4 C + H 2 O + SO 2 (balance this!) Sugar + Sulfuric acid Pure carbon + Water + Sulfur dioxide Observations:
Decomposition Demonstration 2 NaHCO3 --> Na2CO3 + H2O + CO2 Observations: Mass initial Mass final
Combustion Definition Combustion reaction – Hydrogen or a hydrocarbon (H and C) burn in oxygen to produce water and carbon dioxide. Heat is given off as energy. C x H x + O 2 XH 2 O + XCO 2 MENU
Combustion Examples CH 4 + 2O 2 2H 2 O + CO 2 Methane burns in oxygen to produce water and carbon dioxide. C 12 H 22 O O 2 11H 2 O + 12CO 2 A sugar molecule burns in oxygen to produce water and carbon dioxide. MENU
Combustion demonstration Ethanol + Oxygen yields Water + Carbon dioxide C 6 H 12 O 6 + O 2 H 2 O + CO 2
Single Replacement Definition Single Replacement reaction – A single element takes the place of an element in a compound. A + BC B + AC MENU + +
Single Replacement Examples Mg + BeO Be + MgO Magnesium replaces beryllium in beryllium oxide to form magnesium oxide and beryllium. 2Na + 2HCl H 2 + 2NaCl Sodium replaces hydrogen in hydrochloric acid to yield hydrogen and sodium chloride. MENU
Single Replacement Demo. A single replacement of Zinc metal for hydrogen in hydrochloric acid. Zn + 2HCl H 2 + ZnCl 2
Double Replacement Definition Double Replacement reaction – Elements in 2 compounds switch places to form 2 new compounds. AB + CD AD + CB MENU + +
Double Replacement Examples MgO + BeS MgS + BeO Oxygen and sulfur switch places to form magnesium sulfide and beryllium oxide. Na 2 S + Zn(NO 3 ) 2 2Na(NO 3 ) + ZnS Sulfur and nitrate switch places to form sodium nitrate and zinc sulfide.
Make a Venn diagram comparing…. Synthesis vs. Decomposition Single replacement vs. double replacement
What type of reaction? 2 H 2 + O H 2 0
What type of reaction? A + BX AX + B
What type of reaction? AgNO 3 + CuSO 4 AgSO 4 + CuNO 3
What type of reaction is this? 2 HCl (aq) + Zn (s) --> ZnCl 2 (aq) + H 2 (g)
What type of reaction?
Counting atoms How many Carbons are in each of the following compounds: –CO 2 –C 2 H 6 –Na(CO 3 ) 2 –Mg(C 2 O) 4
Warm-up Around the room there are _7__ pictures representing types of reactions. YOUR pictures. Make a list in your notebook, 1- _7__. Try to determine what type of reaction is being represented by the drawing.
Definitions Co-efficient: The number before an element/compound (allowed to change when balancing) –Ex: 2 H 2 Subscript: The small number after an element/compound (NEVER allowed to change when balancing –Ex: 2 H 2
Sacrificial Gummy Bear Demonstrates: –Two types of chemical reactions –HIGHLY Exothermic energy change –Chemical energy converted into thermal, radiant and sound energy
Chemicals used KClO 3 - Potassium chlorate C 12 H 22 O 11 - Sucrose
First reaction KClO 3 (s) KCl (l) + O 2 What type of reaction is this?
First reaction KClO 3 (s) KCl (l) + O 2 Is this reaction balanced? (Make an RT table)
First reaction KClO 3 (s) KCl (l) + O 2 Balance it!
First reaction 2 KClO 3 (s) 2 KCl (l) + 3 O 2 (g)
First reaction 2 KClO 3 (s) 2 KCl (l) + 3 O 2 (g)
Second reaction C 12 H 22 O 11 + O 2 (g) C (s) + CO 2 (g) + H 2 O (g) What type of reaction is this?
Second reaction C 12 H 22 O 11 + O 2 (g) C (s) + CO 2 (g) + H 2 O (g) Is it balanced? (Make an R/P table) If not, balance it! (1 min. early release if done correctly!)
Second reaction C 12 H 22 O O 2 9 C + 3 CO H 2 O Balanced equation
Exothermic Reactions which release energy H = 5635 kJ
How to balance equations 1.) Create a R/P table –(Reactants vs. Products) 2.) Add coefficients to create equal numbers 3.) update the R/P table 4.) Change co-efficients until R = P
Pre-lab/practice Purpose: To generate hydrogen gas –To set norms of behavior when dealing with acid
Locations Ring stands are on top of fume hood Clamps are in 4A All other materials are on counter by sink 1
Materials Ring stand/clamp Test tube 1-2 pea-size chunks of Zn 1 bottle of HCl
Procedure Set up your apparatus as demonstrated Add the Zinc to the test tube Add approximately 2-4 cm of HCl to the test tube Cover with a small piece of aluminum foil Look for signs of a chemical reaction Allow to react for 3-4 minutes
Test Raise your hand when time has elapsed Use the flame test to look for signs of H2 gas
Clean up All test tubes must be cleaned out with Alconox Make sure that all acid is flushed with a large amount of water Sinks are to be totally clean
Homework reminder Read and take notes on pages Answer questions 1 and 2 Due next class