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? Chemical Reactions

Chemical Reactions

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Chemical Reactions. Observing Chemical Reactions. Evidence: The colour changes Bubbles A gas is produced The mixture gets hotter (EXOTHERMIC) or colder (ENDOTHERMIC) 4) A solid (PRECIPITATE) forms from two aqueous solutions. Observing Chemical Reactions. Evidence: - PowerPoint PPT Presentation

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Page 1: Chemical Reactions

? Chemical Reactions

Page 2: Chemical Reactions

? Observing Chemical Reactions

Evidence:1) The colour changes2) Bubbles A gas is produced3) The mixture gets hotter (EXOTHERMIC)or colder (ENDOTHERMIC) 4) A solid (PRECIPITATE) forms from two

aqueous solutions

Page 3: Chemical Reactions

? Observing Chemical Reactions

Evidence:1) The colour changes2) Bubbles A gas is produced3) The mixture gets hotter (EXOTHERMIC)or colder (ENDOTHERMIC) 4) A solid (PRECIPITATE) forms from two aqueous solutions

Dissolved in water

Page 4: Chemical Reactions

? Demo’s

What evidence is there that a chemical reaction has occurred?

Page 5: Chemical Reactions

? Representing Chemical Reactions

In a chemical reaction, one or more substances change to produce new substances.

 • The starting materials are called REACTANTS and the

materials you finish with are called the PRODUCTS. • A plus + sign is used between a list of different

reactants and products. • An arrow is used between the reactants and products

to show that the reactants get turned into the products.

Page 6: Chemical Reactions

? Word Equations

A word equation describes a chemical reaction using the names of the reactants and products.

Examples: Hydrogen + Oxygen water Acetylene + oxygen carbon dioxide + water

Page 7: Chemical Reactions

? Word Equations

A word equation describes a chemical reaction using the names of the reactants and products.

Examples: Hydrogen + Oxygen water 

Acetylene + oxygen carbon dioxide + water

Reactants

Reactants

Products

Products

Page 8: Chemical Reactions

? Practice

Write word equations for the following descriptions. Underline the Reactants and Circle the Products in each.

1) Aluminum metal combines with chlorine gas to make aluminum chloride.

  

  

Page 9: Chemical Reactions

? Practice

Write word equations for the following descriptions. Underline the Reactants and Circle the Products in each.

1) Aluminum metal combines with chlorine gas to make aluminum chloride.

aluminum + chlorine aluminum chloride  

  

Page 10: Chemical Reactions

? Practice

Write word equations for the following descriptions. Underline the Reactants and Circle the Products in each.

  2) Magnesium metal combines with nitrogen gas to make magnesium

nitride.

 

Page 11: Chemical Reactions

? Practice

Write word equations for the following descriptions. Underline the Reactants and Circle the Products in each.

  2) Magnesium metal combines with nitrogen gas to make magnesium

nitride.

magnesium + nitrogen magnesium nitride 

Page 12: Chemical Reactions

? Practice

Write word equations for the following descriptions. Underline the Reactants and Circle the Products in each.

3) Calcium chloride and sodium sulfide solutions are mixed. A precipitate of calcium sulfide and sodium chloride solution is made.

  

Page 13: Chemical Reactions

? Practice

Write word equations for the following descriptions. Underline the Reactants and Circle the Products in each.

3) Calcium chloride and sodium sulfide solutions are mixed. A precipitate of calcium sulfide and sodium chloride solution is made.

Calcium chloride + sodium sulfide calcium sulfide + sodium chloride  

Page 14: Chemical Reactions

? Chemical Equations

A chemical equation is a short hand way of representing a chemical change in which chemical formulas are used for the reactants and products.

Page 15: Chemical Reactions

? States for Substances

The states for the substances may be included using the following symbols:

State Symbol Meaning(s) Solid

(l) liquid

(g) gas

(aq) aqueous

Page 16: Chemical Reactions

? Examples

H2 (g) + O2 (g) H2O (l)

C2H2 (g)+ O2 (g) CO2 (g) + H2O (l)

Page 17: Chemical Reactions

? Reminders

• Don’t forget the diatomic elements: Hydrogen H2 Fluorine F2 Oxygen O2 Chlorine Cl2Nitrogen N2 Bromine Br2

Iodine I2

  Don’t forget to criss-cross the numbers in the ions to

make the subscripts in the compounds. 

Page 18: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

1) sodium + chlorine sodium chloride   

 

Page 19: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

1) sodium + chlorine sodium chlorideNa+ Cl-

   

 

diatomic

Page 20: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

1) sodium + chlorine sodium chlorideNa+ Cl-

Na + Cl2 NaCl   

 

diatomic

Page 21: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

2) fluorine + calcium bromide bromine + calcium fluoride 

Page 22: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

2) fluorine + calcium bromide bromine + calcium fluoride  diatomic diatomic

Page 23: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

2) fluorine + calcium bromide bromine + calcium fluoride  diatomic diatomic

Ca2+ Br- Ca2+ F-

Page 24: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

2) fluorine + calcium bromide bromine + calcium fluoride

F2 + CaBr2 Br2 + CaF2

 

diatomic diatomicCa2+ Br- Ca2+ F-

Page 25: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

3) barium sulfide + potassium iodide barium iodide + potassium sulfide 

Page 26: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

3) barium sulfide + potassium iodide barium iodide + potassium sulfide 

Ba2+ I-K+ I-Ba2+ S2- K+ S2-

Page 27: Chemical Reactions

? Examples

Translate the following word equations into chemical equations:

3) barium sulfide + potassium iodide barium iodide + potassium sulfide 

BaS + KI BaI2 + K2S

Ba2+ I-K+ I-Ba2+ S2- K+ S2-