Name: __________________________________________ Period: ________Unit 7: Chemical Reaction- Guided Notes

Chemical Reactions

Chemical Reaction : one or more substances are changed into one or more new substances by the ___________________________________of component ________________________.

A Chemical Reaction occurs when the _____________________________________ of a substance changes.

How do Chemical Reactions Occur?

The _______________________________ describes the conditions for a reaction to occur The collision theory states that _______________________________ (atoms or molecules) must

________________________________ , with enough _______________________, and in the proper _________________________________ in order for a chemical reaction to occur

o Most collisions result in a reaction however molecule can collide without reacting

Evidence of a Chemical Reaction _____________________________ is produced A _________________________ (a solid) is produced A new _____________________________ is produced Gas is released

o _______________________________________- bubbling from a gas being produced _________________ and/or a __________________________ is produced Heat is __________________________ __________________________ is produced ___________________________ change along with another change The _________________________________________________________________ of the products are

different from the reactants What Evidence of a Chemical Reaction do you see?

Chemical Equations ___________________________________: A representation of a chemical reaction using the formulas of the

starting substances that react and the new substances that are formedo Also called a __________________________________ equation

__________________________________ : the starting substances that enter into a chemical reaction (______________ side of the reaction arrow)

___________________________________: the new substances formed during a chemical reaction (______________ side of the reaction arrow)

____________________: yields or a reaction arrow; separates reactants and productso X + Y XY;o ________________ are reactantso ________________ is the product

Signs and Symbols1

Symbol Meaning+

Heat added Catalyst

States of Matter(s)(l)(g)(aq)

Coefficients : Number ____________________________________________ of a substance showing the number of a particular molecule; apply to ______________________________ in compound/molecule

Subscripts: number __________________________________ an element within a compound showing the number of that element or PAI; applies to ________________________ element

Solubility

_______________________________ solid- a solid that readily dissolves in water (aq) ________________________________ solid- a solid that dissolves to such a small degree that it is not

detectable to the naked eye (s) ______________________________________- An insoluble solid that forms during a chemical reaction (will

look ___________________ or look like a _______________) (s)

Solubility Rules

Solubility Rules- a set of rules/guidelines that indicate whether a substance will be _______________ in water (___) or whether it will be ______________________ in water (____)

Located on the back of your periodic table

Know how to use them

States of matter:o If a substance is soluble, it is __________________________o _____________________ are aqueouso If a substance is insoluble, it is _____________________________o Substances in their elemental form are ____________________ (example: sodium metal)o All the diatomic molecules are ______________________________o Most _______________________________ compounds are gases or liquid

Methane, carbon dioxide, carbon monoxide ______________________ Ammonia is a ____________________________________

o States of other covalent compounds will be indicatedo These rules are true unless otherwise stated

Indicate the state of matter for the following:

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o Sodium Sulfateo Hydrogeno Calcium acetateo Carbonic acido Fe(OH)2

o AlPO4

o LiOHo Carbon monoxideo Silvero PbSO4

Law of Conservation of Mass

___________________________ is neither created nor destroyed in a chemical reaction (atoms are _____________________________)

The starting mass of ______________________ = the final mass of ________________________ Must be obeyed when describing a reaction (shown by __________________________________) Same _________________________ of each element on both sides of the reaction arrow

Balancing Reactions ________________________________________: Show amount of each substance. In front of a compound.

Apply to all elements in the compound. o ___________________________ are used to balanceo SUBSCRIPTS CAN NEVER BE CHANGED!!!

H2O: _________ water molecule; ________ Hydrogen atoms and _______ Oxygen atom 3 H2O : _________ water molecules; __________ Hydrogens and ________ Oxygen atoms Coefficients show ______________________________ of:

o Formula units or molecules involvedo Relative amounts expressed in moles

A balanced equation has the same number of _____________________________on both sides of the equation. Tips to Remember:

o Balance the number of atoms on both sides by adding ________________________________________. DO NOT change the ___________________________________________!!!!

o Must use whole-number coefficients (no ______________________________)o No coefficient means (__________)o Write CORRECT formulas for the reactants and products.

► Remember the 7 _______________________________ gases o Make an element inventoryo Rewrite water as ________________________ if OH is present in the equationo Balance ________________________________ as a group if appear on both sides of the equationo Balance _________________________ and _______________________ lasto If you get stuck, multiple coefficients by _________ and start over (______________________ ONLY)

Practice:

1) ________MgCl2 + ________H2O ________Mg(OH)2 + ________HCl

2) Aluminum sulfate reacts with barium chloride to form aluminum chloride and barium sulfate.

3) Nitrogen gas plus hydrogen gas under pressure and at high temperature turn into ammonia.

Oxidation States3

The oxidation state (also called oxidation ___________________________________) is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound

Oxidation # is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% _______________________, with no _____________________ component.

This is _________________________________ exactly true for real bonds Oxidation numbers are usually the _________________________ of an atom, however not always Oxidation #s are used to determine if a ___________________________ reaction has occurred To do this: Assign elements oxidation #; If an element’s oxidation # ________________________________, then

redox reaction occurred Rules for assigning oxidation #s

1) The oxidation number of any free element or diatomic molecule is ___________________2) The oxidation number of a monatomic ion is equal to the ___________________________ on the ion3) The oxidation number of each hydrogen atom in most compounds is _________ (sometimes ________ if

bonded to a metal)4) The oxidation number of each oxygen atom in most compounds is ______________ (besides peroxide)5) Metals have _______________________ oxidation numbers equal to their charge6) The sum of the oxidation numbers of all the atoms in a particle must equal the _____________________ of

that particle Practice: Determine the oxidation state of each element in the compounds below:

1) H2CO3

2) Br2

3) MgBr2

4) C2H6

Redox Reactions An ____________________________________________________________ reaction involves electron changes Oxidation-reduction reactions are also called ______________________________ reactions ___________________________________ are moved in redox reactions Oxidation and reduction occur at the same time in a reaction. The number of electrons ____________________

must equal the number _____________________________________ A change in the ________________________________________________________ of an atom or an ion

indicates a redox reaction has occurredo No change in oxidation number means a redox reaction did _______________ occur

Substances that lose electrons are ___________________________________o The oxidation number of the element will become more _______________________________

Substances that gain electrons are ________________________________o The oxidation number of the element will become more _________________________________

Remember: “LEO” the lion says “GER”o Lost electrons oxidized; gained electrons reduced

Practice: Determine if the following reactions are oxidation-reduction reactions. If they are redox, determine which substance was oxidized and which substance was reduced:

1) 2H2 + O2 2H2O

2) 2NaCl + CaSO4 Na2SO + CaCl2

3) 2K + 2HCl 2KCl + H2

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Types of Chemical Reactions: ______________________________ Reactions- movement of electron(s)

o ___________________________- occurs when an _________________________ element replaces an element that is part of a compound.

o ___________________________- occurs when ____________________ simple substances combine to form ____________________ more complex substance.

o _____________________________- occurs when ___________________ complex substance breaks down into _____________________________ simpler substances

o ____________________________- a compound is reacted/burned with ________________________ gas to produce _____________________________, _________________________, and ____________________

___________________________________________________ Reactions: occurs when two different compounds react to form two new compounds.

o _________________________________________ Reactions- a precipitate (solid) is formedo _________________________________ Reactions- an acid and a base react to produce a salt and water

There are other types of reactions we will not discuss

Why are Reaction Types Important? Most reactions will fit into one of the types. (There are ____________________.) Scientist use the types of reactions to _______________________________________________.

o Each type follows a ____________________________o If we know the pattern, we can predict the products

Being able to write a chemical equation does not necessarily mean that the reaction will actually take place.

Single Displacement Reactions

A type of ___________________________ reaction An _____________________ element or a _________________________ molecule replaces an element that is

part of a compound Also called single replacement General formula: A + BX AX + B __________________will replace _______________________ and ___________________ will replace

___________________________o What type of ions do metals form? _______________ o What type of ions do non-metals form? _______________o Hydrogen will act as a _______________________ in single

displacemento Rewrite water as _________________________ for single

displacement Requirements: follow the ________________________ ________________________________________: Arrangement of

elements organized in the order of ease with which they undergo certain chemical reactions

o Used to predict products for single displacement reactions only

o There are __________ different activity series _____________________ activity series __________ activity series

o Elements can replace any element __________________ it on the activity series, but NOT any element ____________________ it

o Activity decreases as you move _____________ the groupo Metals _________________ on the list will replace metals _______________on the list.

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o A metal lower on the list will not replace a metal above it on the list; in this case we write _____________for no reaction

o The farther ________________________ 2 elements are on the series, the more likely the higher one will replace the lower one in a compound.

In the following examples, what element is replacing what element? Which element would have to be higher on the list?

o Cu(s) + 2 AgNO3(aq) 2 Ag(s) + Cu(NO3)2(aq)________________________________________________________________________

o 2 Li(s) + 2 H2O (l) 2 LiOH(aq) + H2(g)________________________________________________________________________

Practice: Reaction or No Reaction? Write the products of the reaction or NR for no reaction. Be sure to balance and include states of matter

o Ag (s) + Cu(NO3)2 (aq)

o F2(g) + NaBr(aq)

o I2(g) + NaCl(aq)

o Zn(NO3)2 (aq) + Al(s)

Synthesis Reactions A type of ______________________________ reaction Occurs when _______________________or more simple substances combine to form _________ substance that

is more complex. General formula is A + B AB Examples :

o 2 Fe + 3 Cl2 2 FeCl3

o 2 Na + Cl2 2 NaCl Practice: Write the complete balanced chemical equation for the following synthesis reactions:

o Copper metal reacts with oxygen gas to form copper (II) oxide

_______________________________________________________________________

o Solid sulfur (S8) reacts with oxygen gas to form sulfur dioxide

_______________________________________________________________________

o Aluminum metal reacts with oxygen gas to form…

_______________________________________________________________________

o Calcium metal reacts with nitrogen gas to form…

_______________________________________________________________________

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Decomposition Reactions A complex substance breaks down into ________________ or more simpler substances General formula: AB A + B Do not worry about states of matter Examples:

o Ammonium nitrate decomposes to form dinitrogen monoxide and water NH4NO3 N2O + 2H2O

o Sodium nitride decomposes to form sodium metal and nitrogen gas 2NaN3 2 Na + 3 N2

Practice: Write the complete balanced chemical equation (including states of matter) for the following synthesis reactions:

o Water decomposes into…

________________________________________________________________________

o Solid sodium chloride decomposes into…

________________________________________________________________________

o Liquid ammonia decomposes into..

________________________________________________________________________

Combustion Reactions A type of ____________________________ reaction in which hydrocarbons (substances made of

_______________, _______________, and sometimes ___________) are burned in _____________________ to produce _______________________________ and ____________________________________

These reactions produce a ________________________ and ___________________ All reactants and products are in the ______________ state or _______________ state General formula: CxHy (l) + O2 (g) CO2 (g) + H2O (g)

Examples:o CH4(l) + 2O2(g) CO2(g) + 2H2O(g)o 2C2H6(l) + 7O2 (g) 4CO2 (g) + 6H2O(g)

Practice: Balance the following. Remember Balance hydrogen and oxygen last and if you get stuck, multiple coefficients by 2 and start over (combustion ONLY)

o ___C12H26(g) + ___ O2(g)

o Methane combusts

o Propane gas (C3H8) combusts

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Double Displacement Reactions NOT a _________________ reaction ____________ different compounds react to form _____________ new compounds Also called double ________________________ General formula: AX + BY AY + BX Double displacement reactions:

o ____________________ of the products formed must be: A _____________________ (a solid) A _____________________ (water or will be indicated liquid) A _____________________ (___________________ or will be indicated gas)

Types of Double Displacement reactions:o _____________________________ reaction: a special type of ________________________

displacement reaction in which an ____________________ reacts with a ___________________ to produce a ________________________ and ___________________________.

o ____________________________ reaction: A reaction in which a _______________________ is formed A precipitate is an _________________________ solid Precipitates often look ___________________________________________________________

Examples: o Ca(OH)2 (aq) + 2HCl (aq) CaCl2 (aq) + 2H2O(l)o 2NaOH(aq) + CuCl2(aq) 2NaCl (aq) + Cu(OH)2 (s)o In each of the reactions one of the products is a ___________________, ___________________, or a

______________________.o Identify the reactions above as neutralization, precipitation, or other

Double Displacement Practice: Write and balance the chemical equation for the following reactions. Indicating

state of matter. If the reaction will not take place, write NR (for no reaction) after the reaction arrow. (HINT:

keep the _____________________ where they are and switch the anions and remember to consider charges!)o Barium hydroxide reacts with hydrochloric acid to produce…

o Phosphoric acid reacts with ammonium hydroxide to produce….

o Sodium chloride reacts with lithium bromide to form…

Electrolytes

When a compound dissociates it breaks apart into its ____________________________ A ____________________________ electrolyte dissociates completely when dissolved in water.

o Strong ___________________, strong ________________________, ____________________ ionic salts A _____________________________ electrolyte only dissociates partially when dissolved in water.

o Weak _______________________ and weak ____________________ A ____________________________ does not dissociate when it dissolves in water or does not dissolve in water

o Solids, liquids, and gases

Types of Equations

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_______________________________________equation- lists the reactants and products in their molecular form and indicates state of matter.

o Example: AgNO3 (aq) + KCl (aq) AgCl (s) + KNO3 (aq) __________________________________ equation- shows all strong electrolytes (strong acids, strong bases,

and soluble ionic salts) are dissociated into their ions.o Break apart all _______________________________ substances into ionso This more ____________________________ reflects the species that are found in the reaction mixture.o Do not worry about strong vs. weak acids and bases this unito Ex: Ag+ + NO3

- + K+ + Cl- AgCl + K+ + NO3-

______________________________________________ equation- is an ionic equation where the spectator ions have been eliminated

o A ____________________________________ ion is an ion that exists in the same form on both the reactant and product sides of a chemical reaction.

o If there is no net ionic equation, there is no _______________________________o Example: Ag+ + NO3

- + K+ + Cl- AgCl + K+ + NO3-

o Net Ionic Equation: Ag+ + Cl- AgCl

o Spectator Ions: NO3- and K+

Examples: Write the molecular, ionic, and net ionic equations and determine the spectator ions for the following.

Ex 1: Silver acetate reacts with sodium bromide…

Molecular:

Ionic:

Net Ionic:

Spectator Ions:

Ex 2: Potassium nitrate reacts with sodium fluoride…

Molecular:

Ionic:

Net Ionic:

Spectator Ions:

Ex 3: Hydrochloric acid reacts with potassium hydroxide…

Molecular:

Ionic:

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Net Ionic:

Spectator Ions:

10