Chemical Reactions Unit7

Chemical Reactions Reflect: What is a chemical reaction? Why do they occur?

Chemical Reactions A Chemical Reaction is: A rearrangement of atoms creating a new substance

Chemical Reactions A Chemical Reaction is: Indicated by a color change, bubbles (a gas) or a precipitate (a solid formed).

Chemical Reactions A Chemical Reaction is: Made up of reactants that change into products w/ different properties.

Chemical Reactions A Chemical Reaction is: A rearrangement of atoms creating a new substance Indicated by a color change, bubbles (a gas) or a precipitate (a solid formed). Made up of reactants that change into products w/ different properties.

Word Equations Zn(s) + Pb(NO3)2(aq) -> Zn(NO3)2(aq) + Pb (s) Directions: Write the word equations below as a correct chemical equation. 1). Zinc (s) + Lead (II) Nitrate (aq) yields Zinc Nitrate (aq) + Lead (s) Zn(s) + Pb(NO3)2(aq) -> Zn(NO3)2(aq) + Pb (s)

Word Equations 4Al(s) + 3O2(g) -> 2Al2O3 (aq) 4 Aluminum (s) + 3 Oxygen (g) yields 2 Aluminum Oxide(s) 4Al(s) + 3O2(g) -> 2Al2O3 (aq)

Conservation of Matter Chemical Reactions Conservation of Matter All balanced chemical equations show a conservation of matter by the use of coefficients. For mass to remain constant before and after a chemical reaction the number of atoms of each element must be the SAME before and after a chemical reaction.

Counting Atoms in a Reaction

Chemical Reactions All balanced chemical reactions show a conservation of mass, energy and charge by the use of coefficients in front of each the molecular formulas.

Chemical Reactions For mass to remain constant before and after a chemical reaction the number of atoms of each element must be the same before and after a chemical reaction.  These two statements demonstrate the Law of Conservation of Matter!

Balancing Equations Example 1: Ca + O2  CaO

Balancing Equations Example 2: Na + Cl2  NaCl

Balancing Equations Example 3: FeCl2 + Na3PO4  NaCl + Fe3(PO4) 2

Balancing Equations Example 4: Methane (CH4) reacts with oxygen to make carbon dioxide and water

Balancing Equations Example 5: Fe(s) + O2(g)  Fe2O3(s)

Cu(s) + H2SO4(aq)  CuSO4(aq) + H2O(l) + SO2(g) Balancing Equations Example 6: Cu(s) + H2SO4(aq)  CuSO4(aq) + H2O(l) + SO2(g)

Balancing Equations Example 7: Calcium hydroxide + Phosphoric Acid  Calcium Phosphate + water

Balancing Equations Chemical equations can also include the physical states: (S) indicates a ___Solid_______ (l) indicates ____Liquid________ (g) indicates ____Gas________ (aq) indicates __Aqueous (dissolved in water)

Types of Chemical Reactions Reflect: When looking at a chemical equation what side are the reactants on? What side are the products on? What does the “” mean?

4 Major Types of Chemical Reactions 2H2 + O2 -> 2H2O Two reactants make one product Synthesis = to make something

4 Major Types of Chemical Reactions 2NaCl -> 2Na + Cl2 4 Major Types of Chemical Reactions One reactant breaks up into multiple products Decomposition = breakdown

4 Major Types of Chemical Reactions Mg + CuCl2 -> MgCl2 + Cu The reactant metal that is by itself is more reactive than the metal in the ionic compound 4 Major Types of Chemical Reactions The lone metal is more reactive than the metal in the ionic compound Single replacement= single element switching places with bonded cation Table J

4 Major Types of Chemical Reactions NaCl + Ag(NO3) -> Na(NO3) + AgCl A solid (ppt), gas or water is created in the product 4 Major Types of Chemical Reactions A solid (ppt), gas, or water is created in the products Double replacement = two elements switching places Table f

Single Replacement Reactions Reflect: Look at Table J in your Reference Tables. What is the most reactive metal? What is the most reactive nonmetal? What is the least reactive metal? What is the least reactive nonmetal?

Remember ?

Single Replacement Reactions Single Replacement Reactions: *Where part of an ionic compound is removed and replaced by a new more reactive element.

Single Replacement Reactions Practice comparing the reactivity of elements on Table J: K & Ba Cr & Zn Au & Na F2 & Br2 Cl2 & I2 Al & Br2

Single Replacement Reactions    Single Replacement Reactions will occur if: The element that is by itself is more reactive than the element you are comparing it to in the ionic compound.

Single Replacement Reactions Predicting Single Replacement Reactions: Directions: Use Table J to predict if the single replacement reaction will occur and balance the equation if necessary.   1. Mg(s) + Pb(NO3)2 (aq) 

Single Replacement Reactions 2. Ag(s) + Pb(NO3)2 (aq) 

Single Replacement Reactions 3. Zn(s) + HCl (aq) 

Single Replacement Reactions 4. F2 (g) + NaCl (aq) 

Single Replacement Reactions 5. Cl2 (g) + NaF (aq) 

Applications of Single Replacement Reactions Jewelry! Silver and Gold are prized elements for making jewelry. One reason they make good jewelry is that they are not very reactive. They are above hydrogen on Table J. That’s a good thing so when it rains your jewelry will not be ruined (oxidize)!

Double Replacement Reactions Reflect: What does the word soluble mean? What does the word insoluble mean?

Double Replacement Reactions * Ionic compounds dissolved in water switch partners   Double Replacement Reactions will occur if: You make a gas, water or a precipitate Using Table F to predict solubility: Soluble Compounds: Insoluble Compounds: Compounds that dissolve in Compounds that are solids Water (stay aq) and DO NOT dissolve in water

Using Table F NaNO3: AgCl: CaSO4: MgSO4: Na2CO3: Ba(OH)2: Ca3(PO4)2: HOH: (NH4)OH: PbBr2:

Practice 1. NaI (aq) + Pb(NO3)2 (aq)  2. K2CO3 (aq) + CaSO4 (aq)  3. BaCl2 (aq) + Na2SO4 (aq)  4. BaCl2 (aq) + NaOH (aq) 

Practice 5. Cu(OH)2 (aq) + H2SO4 (aq)  6. Cu(NO3)2 (aq) + NaOH (aq)  7. NiSO4 (aq) + Li3PO4 (aq)  8. MgCl2(aq) + Na2CO3 (aq) 

Practice 9. H2SO4 (aq) + NaOH (aq)  10. NaNO3 (aq) + NH4Cl (aq) 