Presentation on theme: "Do Now (In Do Now Tracker) Grab a reading and focus on the first two pages. Answer the following Questions: 1. What is a chemical reaction as defined by."— Presentation transcript:
Do Now (In Do Now Tracker) Grab a reading and focus on the first two pages. Answer the following Questions: 1. What is a chemical reaction as defined by the reading? 2. Give an example of a common chemical reaction that occurs in everyday life. 2. What is a hydrocarbon? 3. What is the chemical formula for methane? First Do Now Tracker is Due Today Today’s Lesson Topic: Chemical Reactions
Today’s Objective SWBAT to differentiate between reactants and products in a common chemical reaction.
Review… Physical change: a chance where a new substance has not been formed. Atoms can speed up, slow down, change from liquid to solid. Chemical change: atoms in the reactants rearrange themselves and bond together differently to form one or more new products with different characteristics than the reactants. A new substance is formed! Combustion: burning; ignition; a type of chemical reaction
Chemical Reactions Hydrocarbon: molecule made of only carbon and hydrogen. During chemical reactions, two or more substances called REACTANTS interact to create a different substance called PRODUCTS. A candle burning is a chemical reaction, let’s check it out…
Demonstration Question 1: Reactants: wax and oxygen from the air Make another prediction: will the candle still burn if one of the reactants (wax or oxygen) is no longer available? I hypothesize that…
Demonstration Continued… Question 2: Products: carbon dioxide (CO2) and water (H20) Remember… In a chemical reaction, atoms in the reactants combine in new and different ways to form the molecules of the products.
Demonstration Continued… Question 3: Placing a jar over the candle limits the amount of oxygen in the air around the candle. Without enough oxygen to react with the wax, the chemical reaction cannot take place and the candle cannot burn. Question 4: When the candle burns, the candle wax seems to “disappear.” it doesn’t really disappear thought it just reacts chemically, and new products go into the air.
Combustion! Wax is made of long molecules called paraffin (a hydrocarbon). Thus it shows that hydrocarbons burn! Simplest hydrocarbon: methane (the chemical formula is CH4) What is the chemical equation for the combustion reaction?