Update your Table of Contents Write your homework – leave it to be stamped Get a marker from the blue basket and get ready to grade your test also!

Update your Table of Contents Write your homework – leave it to be

stamped Get a marker from the blue basket and

get ready to grade your test also! Get your Adopt-An-Element Baby Book

out, but DO NOT turn it in yet…we are going to grade it!

WARM – UP:WARM – UP:

Date Session#

Activity Page#

10/1610/17

19 Law of Conservation of Mass Notes & Lab 32

Physical & Chemical changes can Physical & Chemical changes can change matter, BUT…THE REAL change matter, BUT…THE REAL

QUESTION IS:QUESTION IS:

During those changes, is any matter created or destroyed?

Law of Conservation of Mass/Matter

Law of Conservation of Mass/Matter- Matter cannot be created or destroyed, it can only change form.

So where does the wood go?

Na F NaF

IN OTHER WORDS…

What goes in, must come out!

The container in which the reaction is performed is open - matter may escape

Open System/ReactionOpen System/Reaction

The container in which the reaction is being performed is closed so all of the matter will be contained – nothing escapes

Closed System/ReactionClosed System/Reaction

Watch the dry ice demo Write ANY observations! Explain how this demonstrates The Law of Conservation of Mass!

Dry Ice DemoDry Ice Demo

Freezing Point of Carbon Dioxide = -108.4oF or -78oCBoiling Point of Carbon Dioxide = -76oF or -57oCFormula: Is this physical or chemical?

CO2(s) CO2(g)

Dry Ice Demo Dry Ice Demo Dry Ice = Solid Carbon DioxideDry Ice = Solid Carbon Dioxide

Law of Conservation of Mass (Matter) Lab Investigation Roles

Group Leader – Reading and making sure the group is following directions accurately and completing all parts of the lab

Supply Manager – Gets, returns & cleans supplies Measurement Technician – gets and returns the

scale balance and is responsible for accurate mass measurements

Data Discussion Technician – makes sure the group records the mass data before and after the experiment, AND everyone has an explanation for THE TEACHER DEMO, STUDENT LAB & COMPARE & CONTRAST

ONE LAB GUIDE WILL BE PICKED FOR THE GROUP GRADE

Law of Conservation of Mass (Matter) Lab Investigation

Send your supply manager to get the lab kit and your measurement technician to get the scale balance.

Group leader, read the directions carefully each step of the way!!◦WARNING: YOUR BALLOON IS ALREADY

FULL OF BAKING SODA, DO NOT TIP IT INTO THE GRADUATED CYLINDER ACCIDENTALLY!

Law of Conservation of Mass (Matter) Lab Investigation Clean-Up Balloons in the garbage Rinse graduated cylinder thoroughly Wipe up any spills Put all items back into your lab kit & put them

on the front counter Put scale balance back onto the back counter Make sure every group member has

measurements and ALL parts of the lab guide are complete

Again, the explanation should state how BOTH experiments demonstrated the Law of Conservation of Mass…BUT,

what were the similarities and differences between them?

Compare & ContrastCompare & Contrast

Update your Table of Contents Write your homework – leave it to be stamped

What does the Law of Conservation of Mass/Matter state?


Date Session#

Activity Page#

10/2010/21

20 Balancing Act Note Guide 33

Balancing Equations Practice 34

What does the Law of What does the Law of Conservation of Conservation of

Mass/Matter state?Mass/Matter state?

Na F NaF

REMEMBER: What goes in, must come out!

Chemical Reactions Reactants – Elements OR compounds present at the beginning of a chemical reaction

Product – Compounds formed by a chemical reaction

REACTANTS

PRODUCT

Balancing Chemical Equations

Since matter can neither be created or destroyed, the

mass/amount of reactants must always equal the

mass/amount of products

Balancing Chemical Equations

Before (Reactants)

After (Product)

Na

F = 1

NaF

Na = 1

F

Na = 1

F = 1

Na F NaF

The arrow indicates that a change has occurred

2H2 + O2 2H2O

(Reactants) (Products)

Chemical formulas

for elements

Chemical formula for new

compound

Subscripts

CoefficientCoefficient Subscrip

t

What is that little number?

Subscript – ◦Shows how many atoms of an element are in a compound.

◦When there is NO subscript there is only 1 atom of that element.

O2 NH4NaCl K5N4C2

What is that big number in front?Coefficient –

◦The number of molecules (compounds) involved in a chemical reaction

H2

H2

O2

H2 O2 H2O2 2

So the coefficient tells you the number of molecules, but what

about each atom? You must multiply…it is like the

distributive property in math!

2NH4 5H2O

2Li3F2 4NaCl 2K5N4C2

3O2

Rules for Balancing Chemical Equations1. You CANNOT change subscripts, you

can ONLY change coefficients

H2 + O2 2H2O

2. It does NOT have to look the same on both sides, it only has to be balanced

3. You CANNOT split compounds to write in a coefficient:

HCl

Rules to Balancing Chemical Equations4. Only multiply through when it is a

compound because they have already bonded

2H + Cl 2HCl NO YES

5. If it is a capital letter, they are each a separate element:

H, C, O If it is a capital letter followed by a lower

case letter, it is all one element:Cl, Li, Si

Steps for Balancing Chemical Equations 1. Divide the reactants from the

products with a line.

2. Write down the chemical symbol of each of the elements on each side of the equation

2 H2 + O 2 2H2O

H =

O =

H =

O =

Steps to Balancing Chemical Equations

3. Using the coefficients and subscripts write down the number of each element

4. If they are not balanced change the coefficients using trial and error. You will have to go back and forth between each side!

2 H2 + O 2 2H2O

H = 4

O = 2

H = 4

O = 2

Lets Practice

P + O2P4O6

Lets Practice

Na + O2Na2O

Lets Practice

Al2O3Al + O2

Lets Practice

Cl2 + KI KCl + I2

Update your Table of Contents Write your homework – leave it to be stamped

Complete the Warm-Up side of the note guide


Date Session#

Activity Page#

10/22 -10/23

21 Endothermic Reactions Vs. Exothermic Reactions

35

Law of Conservation of Mass (Matter)

Law of Conservation of Mass (Matter)- Matter cannot be created or destroyed, it can only change form

In other words…What goes in, must come out!

Law of Conservation of Mass (Matter)

Analyzing Reactions Some chemical reactions are ENDOTHERMIC = take “in” or absorb energy

Some chemical reactions are EXOTHERMIC = give “out” or produce energy

How would you tell the difference?

Endothermic Reactions An endothermic reaction takes “in”

or absorbs energy

Causes temperature around it to cool (will feel cold)

EXAMPLE: Photosynthesis (needs energy from the sun)

An exothermic reaction gives “out” or produces energy (heat, light or sound)

Causes temperature around it to rise (feels warm/hot)

EXAMPLE: cellular respiration (gives energy to your cells)

Exothermic Reactions

Endo & Exo Lab Investigation Roles

Group Leader – Responsible for reading and making sure the group is following directions accurately

Supply Manager – gets and returns supplies and makes sure they are clean

Data Discussion Technician – makes sure the group records all observations and has an explanation for BOTH investigations!

Speaker – Group member that must share your explanation/conclusion with the class.

REVIEWBALANCING

EQUATIONS…Please get your Rules &

Steps for balancing equations out!

Rules for Balancing Chemical Equations1. You CANNOT change subscripts,

ONLY coefficients

H2 + O2 2H2O

2. It does NOT have to look the same on both sides, it only has to be balanced

3. You CANNOT split compounds to write in a coefficient:

HCl

Rules to Balancing Chemical Equations4. Only multiply through when it is a

compound because they have already bonded

2H + Cl 2HCl NO YES

5. If it is a capital letter, they are each a separate element:

H, C, O If it is a capital letter followed by a lower

case letter, it is all one element:Cl, Li, Si

Steps for Balancing Chemical Equations 1. Divide the reactants from the

products with a line.

2. Write down the chemical symbol of each of the elements on each side of the equation

2 H2 + O 2 2H2O

H =

O =

H =

O =

Steps to Balancing Chemical Equations

3. Using the coefficients and subscripts write down the number of each element

4. If they are not balanced change the coefficients using trial and error. You will have to go back and forth between each side!

2 H2 + O 2 2H2O

H = 4

O = 2

H = 4

O = 2

Last Chance to BalanceLast Chance to Balance Balance the 5 equations on the sheet –

if you get them correct you will be using the Chromebooks for the remainder of class to complete the “Study Buddy Review”

If you get them incorrect you will move up to the front counter with me practicing how to balance equations.

REVIEWREVIEW Play the review games listed on the

sheet on top of the Chromebook cart. You may play with a partner if the game

requires 2 players. If you get through all of them ONLY then

can you search for alternate CHEMISTRY RELATED sites/games!!

EXPECTATIONSEXPECTATIONS I expect you and your partner to play only what you are supposed to without being disruptive in any way so that I can focus on helping the people who need it!!

When you are working with me you are expected to complete the equations!!

P + O P4O10

Equation 1 - Balance Box Equation 1 - Balance Box AnswerAnswer

Cl₂ + NaBr NaCl + Br₂


Cs + N₂ Cs3N


CuCl₂ + H₂S CuS +

HCl


Al + HCl AlCl₃ +

H₂


Balancing Equations Practice Balancing Equations Practice HomeworkHomework Find the Balancing Equations Practice

Homework or take another sheet – we will work on a few together, and then you can practice on your own.

Na + MgF2

Lets Practice: Part D - #1Lets Practice: Part D - #1

NaF + Mg

Cl2 + KI


KCl + I2

IMPORTANT:Cl = ChlorineK & I are 2 separate elements

HCl + NaOH


NaCl + H2O

Na + NaNO3


Na2O + N2

PbBr2 + HCl


HBr + PbCl2

Try 6, 7 & 8 on

your own, and then check the answer

key

REVIEWREVIEW

Na3P + CaF2


NaF + Ca3P2

AlBr3 + K


KBr + Al

CaF2 + Li2SO4


CaSO4 + LiF

Documents

Update your Table of Contents Write your homework – leave it to be stamped Get a marker from the blue basket and get ready to grade your test also!