12/8 - 8 th Grade Agenda Learning Objective: Learn about Fire Safety Collect HW: Reading & Notetaking: p.117 – 118 Textbook Reading p. 237-245 HW: Reading & Notetaking p.119 – 122 Reminder HW: Science Fair Background due 1/14 & 1/15 (10 Points)
12/8 - 8th Grade Agenda
Learning Objective: Learn about Fire SafetyCollect HW: Reading & Notetaking: p.117 – 118Textbook Reading p. 237-245HW: Reading & Notetaking p.119 – 122Reminder HW: Science Fair Background due 1/14 & 1/15 (10 Points)
Daily Reflection
• Prompt: What is the difference between an exothermic and endothermic reaction?
What is Conservation of Mass?• The total mass of the reactant must equal the
total mass of the products• During a chemical reaction, matter is not
created or destroyed
Open End vs Closed End systems
What is a coefficient
•2H2 + O2 2H2O
• The number in front of a chemical formula in a chemical is called an coefficient
• It tells you how many molecules or atoms of each reactant or product take part in the reaction
What is a Chemical Equation
• Reactant + Reactant Product + Product
• H2 + O2 H2O2
• Subscript shows the number of atoms of an element in a molecule
Balancing Equation
Types of Chemical ReactionsWhat is a Synthesis?
• When two or more substances (elements or compounds) combine to make a more complex substance, the process is called a synthesis
Types of Chemical ReactionsWhat is Decomposition?
• Decomposition reaction breaks down compounds into simpler products
What is a Replacement reaction?
• It is similar to a girl switching boyfriends
• A reaction in which one element replaces another in a compound
What is an activation energy?
• The minimum amount of energy that has to be added to start a reaction.
• Think of a chemical reaction as being like a rock resting behind a ridge at the top of a hill.
Energy in Chemical Reactions
• Every chemical reaction involves a change of energy. (In the test)
What affects the rate of chemical reactions?
• Concentration• Surface Area• Temperature• Catalysts
What is a Catalyst?
• A Material that increases the rate of a chemical reaction by lowering the activation energy
• What does it mean?
Catalyst Demonstration
• Paper clips represents reactants
• If I place two paper clips in a cup, no matter how hard I shake the cup, I can not get the paper clips to link up.
Catalyst Demonstration
In this model,Paper clip = ReactantDollar bill = Catalyst
Another Catalyst Demonstration
• Hydrogen Peroxide decomposes into Water and Oxygen slowly
• 2H2O2 -> 2H2O + O2
• Yeast acts as a Catalyst and speeds up the reaction.
What is an enzyme or catalyst?
• Enzyme is biological catalyst which provide a surface on which reactions take place.
• This helps reactions happen at lower temperatures because it lowers activation energy.
What is combustion?
• Combustion is a rapid reaction between oxygen and a substance called a fuel.
What are the three things necessary to start and maintain a
fire?• Fuel
• Oxygen
• Heat
What are four common sources of fires at home?
• Small heaters• Fires in the kitchen• Faulty electric wiring• Carelessness with
cigarettes.
How can you fight a fire?
• A. Blow air on it?
• B. Cover it with baking soda?
• C. Use a fire extinguisher?
• D. Pour water on it?
Which of the following is a safety aid in a fire safe home.
• A) smoke detectors
• B) gasoline can in the basement
• C) Fire extinguishers
• D) Box of baking soda in the kitchen