(2.3) TYPES OF CHEMICAL REACTIONS (p )

Word Equation A word equation - states what reacts and what is produced - uses words instead of formulas to describe a chemical reaction

Chemical Reaction Reactants - the starting materials in a reaction. Products - the new materials formed in a reaction.

Chemical Equation Describes a chemical reaction reactants  products Note: The symbol (  ) can be read as yields or forms or produces

Word Equation-Examples Ex 1: magnesium + oxygen  magnesium oxide what reacts what is produced (reactants) (products)

Word Equation-Examples Ex 2: zinc + hydrochloric acid  hydrogen + zinc chloride what reacts what is produced (reactants) (products)

Demo Time! 1) Magnesium reacts with oxygen 2) Copper sulfate decomposes 3) Zinc reacts with hydrochloric acid 4) Lead nitrate reacts with potassium iodide 5) Ethanol burns

CLASSWORK Worksheet 2.3 (A)-complete and hand in REMINDERS: Did you complete and hand in ? - Workbook p Worksheet “Periodic Table” Q # 1-11

Chemical Reactions – 4 Types 4 main types of chemical reactions Synthesis Decomposition Single displacement Double displacement Intro animation (see p145)

1. Synthesis Reactions Two or more reactants combine to form a new product. GENERAL CHEMICAL EQUATION (GCE)

Synthesis Reactions-Examples  sodium + oxygen  sodium oxide  2 H 2 + O 2  2 H 2 O

Synthesis Reaction TomKatie Tomcat

2. Decomposition Reactions A compound is broken down into elements or smaller compounds. GENERAL CHEMICAL EQUATION (GCE)

DDecomposition Reaction BenJenniferBennifer

Decomposition Reactions- Examples  sodium oxide  sodium + oxygen  2 H 2 O  2 H 2 + O 2

Is each reaction synthesis or decomposition? 1. Ag 2 CO 3  Ag 2 O + CO 2 2. P 4 + O 2  P 4 O Fe + O 2  Fe 2 O 3 4. KClO 3  KCl + O 2 Decomposition Synthesis Decomposition Synthesis

Decomposition

3. Single Displacement Reactions One element replaces another element to form a new compound. GENERAL CHEMICAL EQUATION (GCE) Or

Brad & JenAngelina Jennifer Brangelina

Single Displacement- Examples calcium + hydrogen bromide  calcium bromide + hydrogen Br KI +  2 KBr + I 2

4. Double Displacement Reactions In a double displacement reaction the metal ions in two compounds switch places…”partner swap” GENERAL CHEMICAL EQUATION (GCE)

Dawson & Joey Pacey & Jen Pacey & Joey Dawson & Jen

Double Displacement- Examples barium sulfide + potassium iodide  barium iodide + potassium sulfide AgNO 3 + KCl  AgCl + KNO 3

Is it single displacement (SD) or double displacement (DD)? 1. NaBr + Ca(OH) 2  CaBr 2 + NaOH 2. Pb + H 3 PO 4  H 2 + Pb 3 (PO 4 ) 2 3. Li 3 N + NH 4 NO 3  LiNO 3 + (NH 4 ) 3 N 4. CuSO 4 + Al  Al 2 (SO 4 ) 3 + Cu DD SD DD

Putting it all together: Which Type of Reactions are the following: a) H 2 O  H 2 + O 2 b) SiO 2 + HF  SiF 4 + H 2 O c) H 2 + O 2  H 2 O d) Cu + HCl  H 2 + CuCl 2 Single Displacement Double Displacement Synthesis Decomposition

Predict What Gets Made 1. Al + Cl 2  2. CuF 2 + K  3. MgO  4. CaS + FeN  Pick your answer from this box Mg Ca 3 N 2 F 2 KF 2 Cu N 2 AlCl 2 CaFe AlF 3 FeS O 2 SN

Chemical Reactions – 5 th Type Another reaction type is Combustion (also called burning) The burning of fossil fuels always needs oxygen and will yield predictable products. Complete combustion: lots of O 2 Fuel + oxygen  carbon dioxide + water (in general) C x H y + O 2  CO 2 + H 2 O CH O 2  CO H 2 O

5. Combustion Reactions The burning of fossil fuels always requires oxygen and will yield predictable products. Complete combustion: lots of O 2 Fuel + oxygen  carbon dioxide + water CxHy + O 2  CO 2 + H 2 O CH O 2  CO H 2 O

Combustion Continued Incomplete combustion: occurs when there is not enough O 2 The products are different than with complete combustion. CxHy + O 2  C + CO + CO 2 + H 2 O

Chemical Reactions – 5 Types And now a video to summarize: Five Major Chemical Reactions

CLASSWORK WORKBOOK – complete and hand in p

Recall: Chemical Reactions – 5 Types Types of chemical reactions: Synthesis Decomposition Single displacement Double displacement Combustion

Chemical Formulas The chemical formulas of most elements are written simply as the symbol in the periodic table Ex: magnesium, Mg sodium, Na  But there are some elements that contain more than one atom.  For a list, see Table 2.9 p147 or your workbook p55

Chemical Formulas Textbook p 147

Chemical Equation From the word equation you can now write a chemical equation: Ex: a) sodium chloride  sodium + chlorine NaCl  Na + Cl 2 b) hydrogen + oxygen  water H 2 + O 2  H 2 O

CLASSWORK -complete and hand in Worksheet 2.3 (B) Workbook – p