. 9/26/11 62 Chemical Equations 10/13/ Chemical Equations 10/13/2015 Starter: 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 Connection: Balance/Unbalanced Ws Exit: Write the equation for hydrogen and oxygen to water and label it Label: reactants, products, coefficients, subscripts, Chemical equation, elements, and compounds. Practice: Notes: Paste Here Identify the following molecule. Write the chemical formula and how many atoms of each element are in it. EQ: How do chemical reactions obey the law of conservation of mass?

October 13, 2015 AGENDA 8.5 E. I will be able to investigate how evidence of chemical reactions indicate that new substances with different properties are formed by reading, and writing while completing notes and activity 1 Starter 2. Notes 3. Activity 4. Exit

Starter Identify the following molecule. Write the chemical formula and how many atoms of each element are in it. C6C6 H 12 O6O6 Glucose

DateLecture/ Activity/ Lab Page 10/8 Practice Writing Chemical Formulas /12 Writing Chemical Formulas /13 Chemical Equations and the Conservation of Mass Table of Contents

Chemical Equations & the Law of Conservation of Mass 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 Water + Carbon Dioxide Sugar + Oxygen

Decide whether the following statements are physical changes or chemical changes.  A bicycle left out in the rain begins to rust. Chemical  A match burns, leaving only a charred stick of wood. Chemical  A copper wire is cut into five smaller pieces. Physical  An ice cube melts. Physical  Gasoline burns in a car engine. Chemical Let’s review physical and chemical changes!

 A spoonful of sugar is dissolved in a cup of coffee Physical  A silver knife and fork tarnish when they are exposed to air for several weeks. Chemical  Leaves of a maple tree turn bright red as winter approaches. Chemical  Water is heated and changed to steam. Physical  Food is digested in your stomach. Chemical

A chemical equation expresses what happens in a chemical reaction.

Chemical Equations give us specific information about the substances involved in the reaction.

Law of Conservation of Mass Matter cannot be created nor destroyed; only changed. The same amount of matter that goes into a reaction comes out of the reaction.

The chemical equation must be balanced to show that the reactants have the same amount of matter as the products.

Sometimes a reaction produces a gas, which may be difficult to measure. However, if measured, the mass of the reactants will be equal to the mass of the products.

Chemical reactions are written as: Reactants Products “Original stuff” “Yields” “new stuff” CH 4 + 2O 2 CO 2 +2H 2 O Methane + oxygen yields carbon dioxide + wate r

The equation tells us how many atoms and molecules are involved. 2H 2 + 2O 2H 2 O 4 hydrogen atoms 2 oxygen atoms 4 hydrogen atoms 2 oxygen atoms ReactantsProducts

In order to support the law of conservation, the equation must be balanced: The number of atoms of each element to the left of the arrow. Must equal the number of atoms of each element to the right of the arrow. 2H 2 + O 2 2H 2 O H= O= 2 x 2= 4 2 x 1= 22 The equation is balanced! The atoms are just rearranged.

To see if the equation is balanced, just count up the atoms of each element 2Ag + S Ag 2 S Ag= S= The equation is balanced! The atoms are just rearranged.

The subscript is the small number to the right of the symbol. It tells you how many atoms are in each molecule. No number means 1. The coefficient is the large number in front of the molecule. It tells us how many of each molecule. No number means 1. H2OH2O 2H2O2H2O

Remember that you can only change the coefficient to balance an equation __Ag +__ H 2 S __Ag 2 S +__H 2 Ag=Ag= H= H= S= S= / 2 The equation is balanced! 2H2O2H2O

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

. 9/26/11 62 Chemical Equations 10/13/ Chemical Equations 10/13/2015 Starter: 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 Connection: Balance/Unbalanced Ws Exit: Write the equation for hydrogen and oxygen to water and label it Label: reactants, products, coefficients, subscripts, Chemical equation, elements, and compounds. Practice: Notes: Paste Here Identify the following molecule. Write the chemical formula and how many atoms of each element are in it. EQ: How do chemical reactions obey the law of conservation of mass?

V. EXIT Write the equation for hydrogen and oxygen to water and label it Label: reactants, products, coefficients, subscripts, Chemical equation, elements, and compounds..