CHEMICAL REACTIONS TOC 10/17

Today the students will Take notes into their notebook and discuss the differences between chemical formulas and chemical equations.

TEK 8.5D recognize that chemical formulas are used to identify substances and determine the number of atoms of each elements in chemical formulas contain subscripts 8.5E – investigate how evidence of chemical reactions indicate that new substances with different properties are formed.

In the equation above, what is the coefficient of the oxygen molecule? A 0 B 1 C 2 D 4 2Mg + O 2  2MgO 1. Pick a vocabulary word and KISS definition 2. Circle your answer and Justify your choice I. STARTER (write this under the date 10/17)

II. PRACTICE – CHEMICAL REACTIONS Elephant Toothpaste Demonstration 1.Draw and label what you see. 2. Describe what happened 3. How do you know a chemical reaction occurred? List all the signs.

Chemical Equations A chemical equation uses chemical formulas as a shorthand description of a chemical reaction.

LecturePLUS Timberlake7 Writing a Chemical Equation Chemical symbols give a “before-and-after” picture of a chemical reaction Reactants Products MgO + CCO + Mg magnesium oxide yields carbon monoxide reacts with carbon and magnesium

LecturePLUS Timberlake8 Reading A Chemical Equation 4 NH O 2 4 NO + 6 H 2 O Four molecules of NH 3 react with five molecules O 2 to produce four molecules NO and six molecules of H 2 O

LecturePLUS Timberlake9 Law of Conservation of Mass In any ordinary chemical reaction, matter is not created nor destroyed

LecturePLUS Timberlake10 Matter Is Conserved H 2 + Cl 2 2 HCl ++ Total atoms=Total atoms 2 H, 2 Cl 2H, 2 Cl Total Mass=Total Mass 2(1.0) + 2(35.5)2(36.5) 73.0 g=73.0 g

III. APPLICATION Name the reactants in the following equations 2Mg + O 2  2MgO C + O 2  CO 2 2H 2 + O 2  2H 2 O Name the products in the following equations 2CO + O 2  2CO 2 N 2 H 4 + O 2  N 2 + 2H 2 O C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O

LecturePLUS Timberlake12 IV. CONNECTIONS 12 oz of dough, 4 oz mushrooms, 12 slices pepperoni, 8 oz cheese and 5 oz tomato sauce are used to make a pizza. Write a recipe in words for putting together a pizza. How would you write the recipe as an equation?

V. ENDING In the law of conservation of mass (matter), matter can not be created not destroyed only changed. Apply this law to your pizza demonstration in the connection.