Chemical Reactions SPS2. Students will explore the nature of matter, its classifications, and its systems for naming types of matter. d. Demonstrate the Law of Conservation of Matter in a chemical reaction. Purpose: Determine why chemical equations have to be balanced.

Chemical Reaction A process that involves a rearrangement of atoms, molecules, or ions. Substances react together to form new substances with different properties. Examples: Rust, formation of table salt and water

Chemical Equations Reactants → Products Reactants are the substances that undergo change. Products are the new substances produced from the change. Using Equations to Represent Reactions Hydrogen + Oxygen → Water A chemical equation is a representation of a chemical reaction in which the reactants and products are expressed as a formula.

Law of Conservation of Matter The mass of the products is always equal to the mass of the reactants. Mass is neither created nor destroyed in a chemical reaction.

Balancing Equations Water is formed by the reaction of hydrogen with oxygen. H2 + O2 → H2O, if you look at this closely, you will notice the number of O’s on each side is not the same. In order to show that mass is conserved during a reaction, a chemical equation must be balanced.

Balancing Equations Equations can be balanced by changing the coefficients, the numbers that appear before the formulas. The first step to balancing an equation is to count the number of atoms of each element on each side of the equation. 2H2 + O2 → 2H2O, the equation is now balanced.

Chemical Calculations Think about baking. A cake recipe tells you how much of each ingredient is needed to bake one cake. What if you want to make three cakes? Chemical equations can be read as recipes for making new substances.

Chemical Calculations 2H2 + O2 → 2H2O Two molecules of hydrogen react with one molecule of oxygen and form two molecules of water. Two moles of hydrogen react with one mole of oxygen and form two moles of water. 4.0 grams of H2 reacts with 32.0 grams of O2 and forms 36.0 grams of H2O

Chemical Calculations In chemical reactions, the mass of a reactant or product can be calculated by using a balanced chemical equation and molar mass of the reactants and products. Reactants → Products unbalanced H2 + O2 → H2O balanced 2H2 + O2 → 2H2O

Balancing Chemical Equations Using the Tile Method 3 2 __ N2 + __ H2  __ NH3 N2 H2 NH3 H2 NH3 H2

Balancing Chemical Equations Using the Tile Method 2 2 4 __ Na2O2 + __ H2O  __ NaOH + __ O2 Na2O2 H2O NaOH O2 Na2O2 H2O NaOH NaOH NaOH

Activator Know Want to Know Learned Create a KWL chart for Chemical Reactions Know Want to Know Learned

What is a chemical reaction? A process in which atoms of the same or different elements rearrange themselves to form a new substance. While they do so, they either absorb or give off heat. Reactants → Products Reactants are the substances that undergo change. Products are the new substances produced from the change.

What is a chemical equation? A representation of a chemical reaction in which the reactants and products are expressed as formulas. Using Equations to Represent Reactions Hydrogen + Oxygen → Water

Law of Conservation of Matter The mass of the products is always equal to the mass of the reactant. Mass is neither created nor destroyed in a chemical reaction

Activator Balance the following equation ___ H2 + ___ O2  ___ H2O 2 2 H2 O2 H2O H2 H2O

Balancing Chemical Equations Atom Inventory Method SPS2d. Demonstrate the Law of Conservation of Matter in a chemical reaction.

1. Write the chemical equation. C3H8 + O2  H2O + CO2

2. List types of atoms present in the equation. C3H8 + O2  H2O + CO2 Reactants Products C H O

C3H8 + O2  H2O + CO2 Reactants Products C 3 1 H 8 2 O 2 3 3. Count the number of atoms for each element; reactants then products. C3H8 + O2  H2O + CO2 Reactants Products C 3 1 H 8 2 O 2 3

4. Start with the first atom (C) and add coefficients to balance C3H8 + O2  H2O + 3CO2 Reactants Products C 3 1 3 H 8 2 O 2 3 7

5. Now balance the second atom (H) by adding a coefficient. C3H8 + O2  4H2O + 3CO2 Reactants Products C 3 1 3 H 8 2 8 O 2 3 7 10

6. Now balance the last atom type (O). C3H8 + 5O2  4H2O + 3CO2 Reactants Products C 3 1 3 H 8 2 8 O 2 10 3 7 10

Balance the following ___ S8 + ___ O2  ___ SO3 ___ HgO  ___ Hg + ___ O2 ___ Fe + ___ O2  ___ Fe2O3 ___ K + ___ Br2  ___ KBr ___ H2O2  ___ H2O + ___ O2

Balance the following ___ KClO3  ___ KClO4 + ___ KCl ___ P4O10 + ___ H2O  ___ H3PO4 ___ Sb + ___ O2  ___ Sb4O6 ___ N2 + ___ H2  ___ NH3 ___ N2 + ___ O2  ___ N2O

Balance the following ___ Zn + ___ HCl  ___ ZnCl2 + ___ H2 ___ Na + ___ H2O  ___ NaOH + ___ H2 ___ C10H16 + ___ Cl2  ___ C + ___ HCl ___ Fe2O3 + ___ H2  ___ Fe + ___ H2O ___ C7H16 + ___ O2  ___ CO2 + ___ H2O

Balance the following ___ SiO2 + ___ HF  ___ SiF4 + ___ H2O ___ KClO3  ___ KCl + ___ O2 ___ C3H8 + ___ O2  ___ CO2 + ___ H2O ___ Fe2O3 + ___ CO  ___ Fe + ___ CO2 ___ PCl5 + ___ H2O  ___ HCl + ___ H3PO4

Balance the following ___ H2S + ___ Cl2  ___ S8 + ___ HCl ___ Fe + ___ H2O  ___ Fe3O4 + ___ H2 ___ CO2 + ___ H2O  ___ C6H12O6 + ___ O2 ___ SiCl4 + ___ H2O  ___ H4SiO4 + ___ HCl ___ H3PO4  ___ H4P2O7 + ___ H2O

What is wrong with . . . H2 + O2  NaOH 2H2 + O2  2H2O

____ Na + ____ Cl2  ____ NaCl #1 Balance ____ Na + ____ Cl2  ____ NaCl

#2 Balance ____ H2O  ____ H2 + ____ O2

____ CaCO3  ____ CaO + ____ CO2 #3 Balance ____ CaCO3  ____ CaO + ____ CO2

#4 Balance ___ Cu + ___ AgNO3  ___ Ag + ___ Cu(NO3)2

___ K + ___ H2O  ___ H2 + ___ KOH #5 Balance ___ K + ___ H2O  ___ H2 + ___ KOH

___ Pb(NO3)2 + ___ KI  ___ PbI2 + ___ KNO3 #6 Balance ___ Pb(NO3)2 + ___ KI  ___ PbI2 + ___ KNO3

#7 Balance ___ CaCO3 + ___HCl  ___CaCl2 + ___ H2CO3

___ HCl + ___ NaOH → ___ H2O + ___ NaCl #8 Balance ___ HCl + ___ NaOH → ___ H2O + ___ NaCl

#9 Balance ___ Mg + ___ O2 → ___ MgO 

___ MgCO3 → ___ MgO + ___ CO2 #10 Balance ___ MgCO3 → ___ MgO + ___ CO2

#11 Balance ___ KNO3 → ___ KNO2 + ___ O2

#12 Balance ___AgNO3 + ___NaCl → ___NaNO3 + ___AgCl

#13 Balance ___ Ag + ___ S → ___ Ag2S

___ Cl2 + ___ KBr → ___ KCl + ___ Br2 #14 Balance ___ Cl2 + ___ KBr → ___ KCl + ___ Br2

#15 Balance ___ H2 + ___ O2  ___ H2O

#16 Name the Compound N2O3

#17 Name the Compound Al2O3

#18 Write the Formula Iron (IV) Oxide

#19 Write the Formula Potassium Phosphide

#20 Write the Formula Diboron Pentaoxide