What things were mixed What was made Chemical Reactions Chapter 7 Are you into them Intro Reaction Lab Ziploc Science Four Substances Sodium bicarbonate Bromothymol blue Calcium chloride ID: 919042
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Slide1
Smart Starter
What is the last chemical reaction you observed?
What things were mixed? What was made?
Slide2Chemical Reactions
Chapter 7
Are you into them?
Slide3Intro Reaction Lab – Ziploc Science
Four Substances
Sodium bicarbonate
Bromothymol
blue
Calcium chloride
Dihydrogen monoxide (AKA water;)
Slide42 Parts:
Monkey see
,
Monkey do!
Part A
:
Follow the recipe
…~ A+B+CD = AB + CDPART B: Inquiry – Which substances are responsible for each of the observable changes?
LAB Rules? 1. _____ up!
2. ____ before you ___ 3. Don’t ____ _________. Please. Safety Rap
Slide5Here is what happened…
Calcium chloride produces heat (
exothermic
) when it dissolves in water, while sodium bicarbonate absorbs heat (
endothermic
) as it dissolves.
Calcium chloride, baking soda, and water combine to produce carbon dioxide gas. Bromothymol blue is an acid–base indicator that changes color in the presence of acids and bases.
Sodium bicarbonate is a base, so it maintains the blue (basic) color of Bromothymol blue at first. As sodium bicarbonate reacts with calcium chloride in water, acidic substances are produced and the color of the Bromothymol blue indicator changes from the basic form to its yellow, acidic form. Carbon dioxide is one of the acids produced—it dissolves in water and reacts to form carbonic acid, H
2CO3, which makes the water acidic. As carbon dioxide is allowed to escape, the water may turn slightly green or light blue again. The products of the reaction include sodium chloride (NaCl), table salt; calcium carbonate (CaCO3), the main component of chalk; and carbon dioxide (CO
2), the metabolic “waste” gas exhaled during respiration. The events that take place in the zipper-lock bag are part of a dynamic and complex reaction. Intermediate products may be formed and then react further to produce the final composition of the product mixture. The following equation provides a snapshot of the initial and final composition and does not show all of the possible intermediate products.
CaCl2(aq) + 2NaHCO3(aq) + bromothymol
blue
→
CaCO
3
(s) + 2NaCl(
aq
) + H2O (aq) + CO2(g) + bromothymol blue
(acidic form)
(basic form)
Slide67.1 Describing Reactions
Intro Assignment:
Flash Cards
Pictionary
Term on one side
Definitions & Drawings on the other side
Ch
7 Quizlet
Slide7Equations Represent Reactions
Reactant
Product
2H
2
+ O2 2H2O(Coefficients show molar ratios)
Slide8SmartStarter
What is the law of conservation of mass?
Don’t know? Do the best you can to write down what you thing it might be and then See page 193 in your textbook
Slide9SmartStarter
– write the date &
show your work
.
Which of these is most significant AND useful to you in your life?
How did chemistry benefit you today?
Slide10SmartStarter
– write the date &
show your work
.
Since mass is conserved…Balance this equation.
___
Rb
+ ___S8 ---→ ___Rb2S
Bonus: C10H22
+ O2 → CO2 + H2O
REMEMBER: USE A PENCIL!
Slide11SmartStarter
– write the date and
show your work
please
Since mass is conserved…Balance this equation.
___
Rb
+ ___S8 ---→ ___Rb2S
___Rb + ___S8 ---→
_8_Rb2S_
16_Rb + ___S8 ---→ _8_Rb2
S
Bonus:
C
10
H
22 + O2 → CO2
+ H2O_
2_C10H22 + _31_O2
→
_
20
_CO
2
+
_
22
_H
2
O
CHECK YOUR ANSWER!
Rb
– 1
S - 8
Rb
– 2
S - 1
Rb
– 1
S - 8
Rb
– 16S - 8
Rb – 16S - 8
Rb – 16S - 8
Slide12The Law of Conservation of Mass
In any chemical reaction, the final mass of the products
ALWAYS
equals the original mass of the reactants.
In a chemical reaction, mass cannot be added or gained.
The atoms on one side of the equation MUST balance with the atoms on the other side of the equation!
For example:
Na(s) + Cl
2
(g) NaCl(s)
= or = ?
Slide13__Na(s) + Cl2
(g)
__NaCl
(s)
In this case we can add a
coefficientCoefficient is the number in front of the formula. Total # of atoms? coefficient can be multiplied by the subscript (indicating # of atoms) to give the total # of atoms!
2
2
Slide14Slide15Remember!
In order to show that the
mass is conserved
during a reaction,
chemical equations must be balanced
!
REMEMBER: USE A PENCIL!
Slide16Video: Guided Practice – 5 min.
5 Steps
Practice to Learn how to balance!
The
link will show up on
computer
monitor.
Just drag it across to the promethean board (to the right) and make it full screen.
Write the 5 Helps in your NOTES!
Slide17Take
20 minutes
to work on these ten practice problems.
This one is a challenge…if you can’t get it, skip it.
This one is a challenge…KEY: Treat Polyatomic ions as if they are one atom.
1. ________ Cl
2
(g) + _________
NaBr (aq) ---------- _________ Br2(l) + _________ NaCl(
aq)2. ________ Cr2O3
(s) ------------
_________ Cr(s) + __________ O
2
(g)
3. _______ H
3PO4
(aq) + _______ NaOH(
aq) --------- _______ Na3PO4(aq) + _______ HOH(l)
_______ C
2
H
4
(g) + _______ O
2
(g) --------
________ CO
2
(g) + ________ H
2
O(g)
5. ________
Ca
(OH)
2
(s) + _______
HCl
(
aq) -------
________ CaCl2(aq) + ________ HOH(l)
6. _______ CoCl2(aq) + ______ NH4
NO3(aq) ------- _______ Co(NO3)2
(aq) + ______NH4Cl(aq)
7. ________ C6H14(g) + _________ O2(g) --------
__________ CO
2
(g) + _________ H
2
O(g)
_________
K
3
PO
4
(s) + ________
HCl
(
aq
) -----
__________
KCl
(s) + _________ H
3
PO
4
(s
)
_________
C
3
H
8
(s) + _________ O
2
(g) ------
_________ CO
2
(g) + _________ H
2
O (l
)
________
Mg(NO
3
)
2
(s) + ________ K
3
PO
4
(s) -------
_______ Mg
3
(PO
4
)
2
(s) + ______ KNO
3
(s)
Slide18Side Note:
Diatomic Atoms
The diatomic elements are: hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine.
As
elements they always travel in pairs of atoms and therefore you must write then as
: H
2
N2 O2 F2 Cl2 Br2 and I2
Slide19Slide20…Tricks to Balancing
Every atom MUST be balanced
Balance in pencil!!
Start with polyatomic ions that appear only once on each side
Leave H
2
and O
2
and other single element molecules until the end
Do not split up polyatomic ions into separate elements – keep them intact (example: PO
4
– keep P and 4 O together – notice that on the other side of the equation it is also intact)
Write water as HOH – it’s easier to balance with hydroxide (OH)
Do not use fractions – and make sure your final coefficients are in the LOWEST terms
When balancing combustion reactions, notice that oxygen appears twice on the product’s side (CO
2
and H
2
O – the coefficient in front of the H
2
O MUST be an even number – or you will not be able to balance the O
2
on the reactant’s side
Check your final equation – atoms must be equal on both sides of equation
Slide21Counting with Moles
Similar concept: 1 dozen = 12
…in Chemistry
1 mole = a lot.
Specifically:
6.02 X 10
23 AKA: Avogadro’s Number
Get it? How many atoms of Iron are in 1 mole of Fe?
Slide22Molar Mass
The mass of 6.02 X 10
23
Particles
Particles = general term for element/molecule/compound.
Molar mass is the mass (in grams) of 1 mol.
O
f...whatever.Atomic mass # = mass in amuAlso the molar mass of 1 mol. of that element in gramsSo… Atomic mass # = molar mass in gramsTry this: What is the molar mass of O
2?
Slide23Practice
Was the mass conserved?
(# of moles)
Slide24Manipulating Moles Practice
Formula to Molar Mass (g)
Calculate the molar mass of
Al(NO
3
)
3How many moles of Al(NO3)
3 is that?Grams to MolesIf I have 639g of Al(NO3)3, how many moles do I have?
Moles to GramsWhat is the mass (g) of 5 moles of Al(NO3)3?
Resources/Help Videos
Slide25Click to link to 7.5 min. video
How to Calculate Molar Mass - Video
Take Notes so you will be ready to succeed in the next practice set of questions!
STUDENTS: Take Notes on how to calculate moles from grams & grams from moles
Slide26Grams to Moles & Moles to Grams
Slide27Molar Mass Practice HO
Question 2
Calculate the molar mass of CaCOH.
Question 3
Calculate the molar mass of Cr
4
(P
2
O
7
)
3
.
Question 4
Calculate the molar mass of RbOH·2H
2
O.
Question 5
Calculate the molar mass of
KAl
(SO
4
)
2
·12H
2
O.
Question 6
What is the mass in grams of 0.172 moles of NaHCO
3
?
Question 7
How
many moles
of CdBr
2
are in a 39.25 gram sample of CdBr
2
?
Question 8
How
many atoms
of cobalt are in a 0.39
mole sample
of Co(C
2
H
3
O
2
)
3
?
Question 9
What is the mass in milligrams of chlorine in 3.9 x 10
19
molecules of Cl
2
?
Question 10
How
many grams
of aluminum are in 0.58 moles of Al
2
O
3
·2H
2
O?
Question
1
Calculate
the molar mass of CuSO
4
.
If needed:
More detailed explanation:
10 minute – Molar Mass Calculations
Use the rest of the class period to complete this assignment.
*At the end of class turn in the handout with your name on it…
even if you didn’t finish.
6 minutes – help on converting moles to grams and grams to moles.
No phones!
CALCULATORS ARE AT THE FRONT.
Slide28Molar Mass Calculation Practice
Answers
Slide29SmartSTARTER
What is the molar mass of
Slide307.2 Types of Reactions
Slide314 Types Of Reactions
In chemistry there are millions of chemical reactions. But most reactions can be classified as one of
4 types:
Synthesis: A + B ->
AB
Decomposition
: AB -> A + BSingle
Replacement: A + BC -> AC + BDouble Replacement: AB + CD -> AD + CB Here is a short explanation and examples of each type of reaction.
Slide32Type 1: Synthesis (Composition)
In a synthesis reaction (also known as a composition reaction), two substances combine
to
form a larger substance.
Analogy: boy
A walks into the dance, sees girl B and ask her to dance. They then form couple AB.
Synthesis: A + B -> AB
Slide33Here are four synthesis reactions
:
Hydrogen + oxygen yields water
2H
2
+ O
2
-> 2H
2
O
Magnesium + nitrogen yields magnesium nitride
3Mg + N
2
-> Mg
3
N
2
Iron + sulfur yields iron(II) sulfide
Fe + S ->
FeS
Sodium
+ phosphorus yields
sodium
phosphide
3Na + P -> Na
3
P
Simplest Type Of
Synthesis Reaction
= two elements combine to form a compound
Slide34Side Note:
Diatomic Atoms
The diatomic elements are: hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine.
As
elements they always travel in pairs of atoms and therefore you must write then as
: H
2
N2 O2 F2 Cl2 Br2 and I2
Slide35Type 2
: Decomposition
In a decomposition reaction, a larger
substance
breaks apart and forms two or more simpler substances.
D
ancers Analogy
:
boy A steps on girl B's toe. She gets upset and walks away.
Slide36Type 3: Single Replacement
In a single replacement reaction, a more active element replaces a less active element in a compound
.
Analogy…
Slide37Example
If fluorine gas is bubbled through a solution of potassium chloride, the fluorine will replace the chlorine
.
2KCl
+ F
2
--> 2KF + Cl
2
Slide38Type 4: Double Replacement
In a double replacement reaction, two metal ions
(
cations
-in
aqueous compounds) switch places
.
Analogy
of dancers: Two couples are dancing . The two girls look over and state they wish to switch partners. And so...they do.
Slide39Double Replacement Examples
Slide40Combustion Reaction
Rapid Reaction with Oxygen
Produces light and heat.
Anyone feeling cold today?
___C
2
H
6O + ___O2 ___H2
O + ___CO2
Slide41Oxidation-Reduction Reaction
=
Redox
Reaction where an element loses electrons
Electrons are transferred from one reactant to another.
Fe
2
O3(s) + 2Al(s) Al2O3(s) + 2Fe(l)
Loses electron = oxidation, reactant is oxidizedGaines electrons = reduction, reactant is reduced
Slide427.3 Energy Changes in Reaction
Energy is either released or absorbed in reactions
Chemical Bonds are either broken or formed
Slide43Law of Conservation of
Energy
Total amount of energy before and after is the same
Slide44Endothermic
vs.
Exothermic
Endo
– in
Exo
– out
-therm – thermal energyEndothermic – net gain of energy - absorbsMore energy is required to break the bonds, than is released when the products form.
Exothermic – net loss of energy - releasesMore energy is released as the products form is less than the energy required to break the bonds in the reactants.
Slide45Which is it based on this graph?
DRAW A GRAPH OF A ENDOTHERMIC REACTION !
Endothermic or Exothermic?
Slide46KEY QUESTION: What is the
net
result for the whole system?
Slide477.4 Reaction Rates
What would affect the rate of a chemical reaction?
DATING and Reaction RATES
(5 min.)
Slide48Factors that Affect Reaction Rate
Concentration
Stirring
Temperature
Surface Area
Catalysts
Slide497.5 Equilibrium & Reversible Reactions
Slide50REVIEW CHEM. RCN.
Kahoot
:
Exam III Easy Review
Quizlet Live:
Ch
7 Quizlet
Slide51LAUNCH
“If you fail to plan, you plan to fail.”
THOSE WITH A PLAN WIN.
Home Work:
Enjoy family time!
Slide52P2
Slide53P3
Slide54P4
Slide55P5
Slide56P7
Slide57Examples
1. ________ Cl
2
(g) + _________
NaBr
(
aq) ---------- _________ Br2(l) + _________ NaCl(aq)
2. ________ Cr2O3
(s) ------------ _________ Cr(s) + __________ O2(g)
3. _______ H3PO4(aq) + _______
NaOH
(
aq
) ---------
_______ Na
3PO4(aq) + _______ HOH(l)
_______ C2H4(g) + _______ O2(g) -------- ________ CO2
(g) + ________ H
2
O(g)
5. ________
Ca
(OH)
2
(s) + _______
HCl
(
aq
) -------
________ CaCl
2
(
aq
) + ________ HOH(l)
6. _______ CoCl
2(aq) + ______ NH4NO3
(aq) ------- _______ Co(NO3)
2(aq) + ______NH4Cl(aq)
7. ________ C6H
14(g) + _________ O2(g) -------- __________ CO2(g) + _________ H2O(g)
Slide58Examples
1. ________ Cl
2
(g) + _________
NaBr
(
aq) ---------- _________ Br2(l) + _________ NaCl(aq)
2. ________ Cr2O3
(s) ------------ _________ Cr(s) + __________ O2(g)
_______ C2H4(g) + _______ O2(g) --------
________ CO
2
(g) + ________ H
2
O(g)
5. ________ Ca(OH)
2(s) + _______ HCl(
aq) ------- ________ CaCl2(aq) + ________ H2O(l)
Challenge!
6
. ________ C
6
H
14
(g) + _________ O
2
(g) --------
__________ CO
2
(g) + _________ H
2
O(g)
7.
_______ CoCl
2
(
aq) + ______ NH4NO3(aq) -------
_______ Co(NO3)2(aq) + ______NH
4Cl(aq)
Slide59Slide60Speed Dating!
Slide61Date 1
Hello, my name is __________________.
1
st
person – give answer
2
nd
person – explain why it is the right answerWrite it down.
Slide62Date 2
Hello, my name is __________________.
(write your date’s name on your answer sheet)
1
st
person – give answer
2
nd person – explain why it is the right answer and the others are wrongWrite it down. Explain.
Slide63Date 3
Hello, my name is __________________.
(write your date’s name on your answer sheet)
1
st
person – give answer
2
nd person – explain why it is the right answer and the others are wrongWrite it down. Explain.
Slide64Date 4
Hello, my name is __________________.
(write your date’s name on your answer sheet)
1
st
person – give answer
2
nd person – explain why it is the right answer and the others are wrongWrite it down. Explain.
Slide65Date 5
Hello, my name is __________________.
(write your date’s name on your answer sheet)
1
st
person – give answer
2
nd person – explain why it is the right answerWrite it down. Explain.
1.
Slide66Date 6: Feedback
No Names!
1. Hello, my name is __________________.
(write your date’s name on your answer sheet)
2. What made your best date good?
3. What was something you thought could be done better in some of your “dates”?