Chemical Reactions. Conservation of Matter The law of conservation of mass says that matter cannot...

Chemical ReactionsChemical Reactions

Conservation of MatterConservation of Matter

The law of conservation of mass says The law of conservation of mass says that matter cannot be created or that matter cannot be created or destroyed.destroyed.

Even during a chemical reaction, the Even during a chemical reaction, the mass of the things you put in must mass of the things you put in must equal the mass of the things that are equal the mass of the things that are made during the reaction.made during the reaction.

Conservation of Matter ActivityConservation of Matter Activity

You must wear goggles during this You must wear goggles during this experiment. experiment.

Follow directions carefully.Follow directions carefully.Group activity rules apply.Group activity rules apply.

Group Activity RulesGroup Activity Rules

You must stay in your assigned group You must stay in your assigned group at your table unless you have at your table unless you have permission to move around the room.permission to move around the room.

No horseplay!No horseplay!Any behavior issues will result in a 0 Any behavior issues will result in a 0

on the assignment and possibly a trip on the assignment and possibly a trip to the office.to the office.


What this means is that the number of What this means is that the number of atoms of each element that go into a atoms of each element that go into a reaction must equal the number of reaction must equal the number of atoms that come out of the reaction.atoms that come out of the reaction.


Atoms are not created or destroyed Atoms are not created or destroyed during a chemical reaction.during a chemical reaction.

Scientists know that there must be Scientists know that there must be the same number of atoms on each the same number of atoms on each side of a chemical equation.side of a chemical equation.

Balancing EquationsBalancing Equations

To balance a chemical equation, you To balance a chemical equation, you must add coefficients in front of the must add coefficients in front of the chemical formulas in the equation.chemical formulas in the equation.

You cannot change or erase the You cannot change or erase the subscripts.subscripts.

Chemical EquationsChemical Equations

Chemical equations show us what is Chemical equations show us what is happening during a chemical reaction.happening during a chemical reaction.

2Mg + O2Mg + O22 2MgO 2MgOThe elements or compound(s) on the left The elements or compound(s) on the left

side are the reactants.side are the reactants.The elements or compound(s) on the right The elements or compound(s) on the right

side are the product(s)side are the product(s)

Chemical EquationsChemical Equations

The coefficients show us how many of The coefficients show us how many of each molecule are reacted or produced in each molecule are reacted or produced in the reaction.the reaction.

What does the arrow mean?What does the arrow mean?

Candy ChemistryCandy Chemistry

We are going to look at what happens on We are going to look at what happens on an atomic level in a chemical reaction an atomic level in a chemical reaction using colored marshmallows to represent using colored marshmallows to represent the atoms of different elements and the atoms of different elements and toothpicks to represent the bonds between toothpicks to represent the bonds between atoms.atoms.

Balancing Reactions ActivityBalancing Reactions Activity

Each group will have one set of Each group will have one set of cards.cards.

Separate the cards into three groups:Separate the cards into three groups:NumbersNumbers+, arrow, reactants, products+, arrow, reactants, productsChemical compoundsChemical compounds


Put the Reactants card on the left and Put the Reactants card on the left and put the cards for the reactant(s) put the cards for the reactant(s) below.below.

Put the arrow to the right of the Put the arrow to the right of the reactantsreactants

Put the Products card on the right and Put the Products card on the right and put the cards for the product(s) belowput the cards for the product(s) below


Count the number of atoms for each of the Count the number of atoms for each of the elements on the Reactants side.elements on the Reactants side.

Write the symbols and numbers in the Write the symbols and numbers in the Reactants column in Table 1.Reactants column in Table 1.

Count the number of atoms for each of the Count the number of atoms for each of the elements on the Products side.elements on the Products side.

Write the symbols and numbers in the Write the symbols and numbers in the Products column in Table 1.Products column in Table 1.


Use the coefficients to make the Use the coefficients to make the numbers of atoms of each element numbers of atoms of each element equal on both sides (balanced).equal on both sides (balanced).

When you have a balanced equation,When you have a balanced equation,Write the symbols and NEW numbers in Write the symbols and NEW numbers in

the Reactants column in Table 1.the Reactants column in Table 1.Write the symbols and NEW numbers in Write the symbols and NEW numbers in

the Products column in Table 1.the Products column in Table 1.HINT: They should be equal!HINT: They should be equal!


Write the balanced equation Write the balanced equation (including reactants, product, and (including reactants, product, and correct coefficients) in the balanced correct coefficients) in the balanced equation column on Table 1.equation column on Table 1.

When you have the balanced When you have the balanced equation, raise your hand, and I will equation, raise your hand, and I will check it off.check it off.

Types of ReactionsTypes of Reactions

Partners ActivityPartners Activity

How are people like chemicals in How are people like chemicals in reactions?reactions?Boy and girl are attracted to each otherBoy and girl are attracted to each other

Makes a new couple (compound)Makes a new couple (compound)SynthesisSynthesis

A + B A + B AB AB

Partners ActivityPartners Activity

How are people like chemicals in How are people like chemicals in reactions?reactions?Boy and girl are no longer attracted to Boy and girl are no longer attracted to

each othereach otherBreak up (makes separate Break up (makes separate

compounds)compounds)DecompositionDecomposition

AB AB A + B A + B

Partners ActivityPartners ActivityHow are people like chemicals in How are people like chemicals in

reactions?reactions?Boy (or girl) is more attracted to another Boy (or girl) is more attracted to another

boy (or girl)boy (or girl)One replaces the other (new One replaces the other (new

compound and single element)compound and single element)Single ReplacementSingle Replacement

AB + C AB + C CB + A CB + A

Partners ActivityPartners ActivityHow are people like chemicals in How are people like chemicals in

reactions?reactions?Boy and girl replace each other in Boy and girl replace each other in

couplescouplesTwo new couples (two new Two new couples (two new

compounds)compounds)Double ReplacementDouble Replacement

AB + CD AB + CD AD + CB AD + CB

Reaction Types DemonstrationReaction Types DemonstrationSynthesisSynthesis

A + B A + B AB AB

2Mg + O2Mg + O22 2MgO 2MgOSingle ReplacementSingle Replacement

AB + C AB + C CB + A CB + A

2HCl + 2Zn 2HCl + 2Zn 2ZnCl + H 2ZnCl + H22

Reaction Types DemonstrationReaction Types DemonstrationDouble ReplacementDouble Replacement

AB + CD AB + CD AD + CB AD + CB

2NaOH + CuCl2NaOH + CuCl22 2NaCl + Cu(OH) 2NaCl + Cu(OH)22

DecompositionDecomposition

AB AB A + B A + B

2H2H22OO22 2H 2H22O + OO + O22

““Brady Bunch” DiagramBrady Bunch” Diagram

Fold your paper in thirds horizontally and Fold your paper in thirds horizontally and verticallyvertically

You should have nine rectangles (like this)You should have nine rectangles (like this)


Write “Reaction Types” in the middleWrite “Reaction Types” in the middleMake a square with the name of each Make a square with the name of each

reaction type and leave a blank square reaction type and leave a blank square between each onebetween each oneSynthesisSynthesisSingle ReplacementSingle ReplacementDouble ReplacementDouble ReplacementDecompositionDecomposition


In the square next to each reaction type, In the square next to each reaction type, write an equation or a picture of what is write an equation or a picture of what is happening for that type.happening for that type.

Either write the reaction type in the Either write the reaction type in the equation or picture square or draw an equation or picture square or draw an arrow from the reaction type.arrow from the reaction type.

Identifying Reaction TypesIdentifying Reaction Types

Look at the reactants and the products:Look at the reactants and the products:Does the reaction have two reactants Does the reaction have two reactants

combining to form one product? combining to form one product? SynthesisSynthesis

Does the reaction have one reactant Does the reaction have one reactant coming apart to form two products? coming apart to form two products? DecompositionDecomposition


Look at the reactants and the products:Look at the reactants and the products:Does the reaction have any reactants Does the reaction have any reactants

that contain only one element? that contain only one element? Single ReplacementSingle Replacement

Does the reaction have two reactants Does the reaction have two reactants made up of two elements switching their made up of two elements switching their ions to form two products? ions to form two products? Double ReplacementDouble Replacement


PracticePractice3Pb + 2H3Pb + 2H33POPO44 3H 3H22 + Pb + Pb33(PO(PO44))22

2H2H22 + O + O22 2H 2H22OO

2NaBr + Ca(OH)2NaBr + Ca(OH)22 CaBr CaBr22 + 2NaOH + 2NaOH

NHNH44OH OH NH NH33 + H + H22OO

More PracticeMore Practice

PracticePracticeFe + CuSOFe + CuSO44 FeSO FeSO44 + Cu + Cu

MgO + HMgO + H22O O Mg(OH) Mg(OH)22

2NaCl + Ca(OH)2NaCl + Ca(OH)22 CaCl CaCl22 + 2NaOH + 2NaOH

CaCOCaCO33 CaO + CO CaO + CO22

More PracticeMore Practice

Balance and Classify by Type:Balance and Classify by Type:HF + OHF + O22 H H22O + FO + F22

NHNH33 + H + H22O O NH NH44OHOH

NaI + Pb(NONaI + Pb(NO33))2 2 PbI PbI22 + NaNO + NaNO33

NaOCl NaOCl NaCl + O NaCl + O22

Chemical Reactions. Conservation of Matter The law of conservation of mass says that matter cannot...

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