Transcript remaster unit 8A + 7

Warm Up
Predict the products of the
following 2 reactions:
1. NaCl + MgF2 → ? + ?
2. Calcium oxide and barium
sulfide → ? and ?
Take 1
What to do???
• Make sure you have a tracking sheet (all
versions are the same)
• Get calculators from the bin. Return them
when finished
• Complete ALL parts of tracking sheet
• Raise hand to ask questions
• You may track a classmate’s for extra
credit…make sure to put their name on it
Chemical Reactions
Situation where atoms
rearrange to make new
substances.
Reactants
BEFORE
•What you start with.
•What reacts or rearranges
Reactants
Products
AFTER
BEFORE
•What you start with.
•What you end with.
•What is produced.
•What reacts or rearranges
Double Replacement
• How to predict products?
– Just switch partners
– Cations (positive ions) still come first in the
formula
– Anions (negative ions) still come last in the
formula
– Polyatomic ions move as a unit
– Example?
Practice Double Replacement (aka
partner switch!)
What forms from:
1. Calcium sulfide and magnesium oxide
2. Potassium chloride and hydrogen
carbonate
3. Sodium hydroxide and lithium bromide
Practice Double Replacement (aka
partner switch!)
What forms from:
1. NaCl and LiF
2. CaO and MgS
3. MgCl2 and CaI2
4. CaF2 and Li2O
Kris Kross Method!
2+
3Ca As
Ca3As2
Write down the stable ions
and cross the oxidation
numbers (charges) to make
them subscripts
1+
1Na Cl
NaCl
4+
2Pb O
Pb2O4
Write down the stable ions
and cross the oxidation
numbers (charges) to make
them subscripts
1+
1Na Cl
NaCl
4+
2Pb O
Pb2O4
Write down the stable ions
and cross the oxidation
numbers (charges) to make
them subscripts
1+
1Na Cl
NaCl
4+
2Pb O
Pb2O4
Extra Rules
• DON’T cross signs (+ or -)
• DON’T cross 1’s
• If the numbers are the same, DON’T cross
them (if both are 3’s, don’t cross them)
• Reduce final subscripts if able to
Ionic Compounds
K F
Ba N
Ga O
K Si
Ca Cl
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
+
KF
Ba N
Ga O
K Si
Ca Cl
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
KF
Ba N
Ga O
Ca Cl
K Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
2+
3Ba N
KF
Ga O
K Si
Ca Cl
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
KF
Ba3N2
Ga O
Ca Cl
K Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
KF
Ba3N2
3+
2Ga O
K Si
Group
Charge
Ca Cl
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
KF
Ba3N2
Ga2O3
Ca Cl
K Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic Compounds
KF
Ba3N2
2+
Ca Cl
Ga2O3
K Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic compounds
KF
Ba3N2
Ga2O3
CaCl2
K Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Ionic compounds
KF
Ba3N2
Ga2O3
CaCl2
+
4K Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Balancing Chemical Reactions
KF
Ba3N2
Ga2O3
CaCl2
K4Si
Group
Charge
1 2 3 4 5 6 7 8
1+ 2+ 3+ 4- 3- 2- 1- 0
Remastery quiz
• Work silently and alone for full credit
Matter is Conserved!
If mass is never created/destroyed, and it can
be measured, then:
Key Point 3: Total mass of products = Total
mass of reactants
Now Let’s Apply:
A student takes 30g of BaCl2 and reacts it
with 25 g of LiOH.
BaCl2 + LiOH  LiCl + Ba(OH)2
What is the total mass of the products
formed?
Now Let’s Apply:
A student takes 30g of BaCl2 and reacts it
with 25 g of LiOH.
BaCl2 + LiOH  LiCl + Ba(OH)2
What is the total mass of the products
formed?
55g.
Practice, Practice, Practice
• 45g of K3PO4 are combined with 25g of
NaOH.
What is the total mass of products?
35g of MgSO4 are combined with 30g of KCl
What is the total mass of products?
Practice, Practice, Practice
• 45g of K3PO4 are combined with 25g of
NaOH.
What is the total mass of products? 70g
35g of MgSO4 are combined with 30g of KCl
What is the total mass of products?
Practice, Practice, Practice
• 45g of K3PO4 are combined with 25g of
NaOH.
What is the total mass of products? 70g
35g of MgSO4 are combined with 30g of KCl
What is the total mass of products? 65g
Practice, Practice, Practice
• 70g of BaCl combines with 50g of NaOH
What is the total mass of products?
253.4g of NaOH combines with 123.4g of
LiCl
What is the total mass of products?
Practice, Practice, Practice
• 70g of BaCl combines with 50g of NaOH
What is the total mass of products? 120g
253.4g of NaOH combines with 123.4g of
LiCl
What is the total mass of products?
Practice, Practice, Practice
• 70g of BaCl combines with 50g of NaOH
What is the total mass of products? 120g
253.4g of NaOH combines with 123.4g of
LiCl
What is the total mass of products? 376.8g
Practice, Practice, Practice
• 70g of BaCl combines with 50g of NaOH and
forms 60 g of BaOH.
• What is the mass of the NaCl that forms?
250g of NaOH combines with 125g of LiCl and
forms 100 g of NaCl.
What is the mass of the LiOH that forms?
Practice, Practice, Practice
• 70g of BaCl combines with 50g of NaOH and
forms 40 g of BaOH.
• What is the mass of the NaCl that forms? 80g
250g of NaOH combines with 150g of LiCl and
forms 100 g of NaCl.
What is the mass of the LiOH that forms? 300g
Remastery quiz
• Work silently and alone for full credit
Balancing equations RULES!
• When balancing
equations, Never, Never,
NEVER change
subscripts, only
coefficients!
But Ms. Hughes…
• What is a coefficient?
•GOOD QUESTION!
Coefficient
• A coefficient is a whole number in front of
the compound, never in the middle!
• You multiply the coefficient to all the
subscripts in the compound
2AlCl3
Do you get it?
• 3AlCl3
• How many atoms of each element do they
have?
• ? Aluminum’s
• ? Chlorine’s
Practice
•
•
•
•
•
2AlCl3
4H2O
6H2O2
5KCl
2Be3S2
Balancing Chemical Reactions
H2 + O2  H2O
__H__
__O__
Write down elements.
Balancing Chemical Reactions
H2 + O2  H2O
__H__
__O__
How many are there?
Balancing Chemical Reactions
H2 + O2  H2O
_2_H_2_
__O__
How many are there?
Balancing Chemical Reactions
H2 + O2  H2O
_2_H_2_
_2_O_1_
How many are there?
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
Mg(s) + O2(g)  2MgO
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
Na(s) + O2(g)  Na2O(s)
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
2Al(s) + Cl2(g)  Al2Cl3(s)
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
Br2 + O2  2Br2O
Balancing Equations
1) Determine number of atoms for each element.
2) Pick an element that is not equal on both sides
of the equation.
3) Add a coefficient in front of the formula with that
element and adjust your counts.
4) Continue adding coefficients to get the same
number of atoms of each element on each side.
Balancing Chemical Reactions
H2 + O2  H2O
_2_H_2_
_2_O_1_
How many are there?
Balancing Chemical Reactions
Try These:
N2 + H2  NH3
P4O10 + H2O  H3PO4
Ca3P2 + H2O 
Ca(OH)2 + PH3
Balancing Chemical Reactions
Try These:
N2 + 3H2  2NH3
P4O10 + H2O  H3PO4
Ca3P2 + H2O 
Ca(OH)2 + PH3
Balancing with some hot
sauce…
What if you have some polyatomic ions?
WHAAAAAAAAT will you do??
When balancing
equations with
polyatomic
ions, keeping
them together
can make it
easier!
Work it out…
H3PO4 + ____ KOH  ____ K3PO4 + ____ H2O
• Which polyatomics are we using?
– PO4 – phosphate
– OH – hydroxide
• Where is the OH on the other side?
– It’s okay – rewrite H2O as HOH
– Trust me!
Balancing Chemical Reactions
Try These:
N2 + 3H2  2NH3
P4O10 + 6H2O  4H3PO4
Ca3P2 + H2O 
Ca(OH)2 + PH3
Balancing Chemical Reactions
Try These:
N2 + 3H2  2NH3
P4O10 + 6H2O  4H3PO4
Ca3P2 + 6H2O 
3Ca(OH)2 + 2PH3
Remastery quiz
• Work silently and alone for full credit
Warm Up
1. Does breaking a bond absorb or release
energy?
2. Does forming a bond absorb or release
energy?
3. How is an exothermic reaction different
from an endothermic reaction?
Why does the temperature
change?!?
Key Point #1:
Breaking a bond requires energy.
Forming new bonds releases
energy.
Unit for energy: kilojoules (kJ)
Endothermic
=
energy ABSORBED
energy goes IN
Exothermic
=
energy RELEASED
energy EXITS
Endo or Exo???
1. 2 HCl + 185 kJ  H2 + Cl2
2. 4 NH3 + 5 O2  4 NO + 6 H2O + 1169
kJ
3. Cu + Cl2  CuCl2 + 220.1 kJ
4. H2O + C + 132 kJ  CO2 + 2H2
Some Questions to ponder
The combustion of the hydrocarbon
glucose (C6H12O6) produces
carbon dioxide, water, and
releases 2830 kJ.
Exo or Endo???
Some Questions to ponder
After absorbing 66.4 kJ of energy, 1
mole of nitrogen gas and 2
moles of oxygen gas react to
form 2 moles of nitrogen
monoxide.
Exo or Endo???
Remastery quiz
• Work silently and alone for full credit
• Remember to look up the names of
polyatomic ions
• Gases like oxygen, etc are O2
– “diatomic”
• + means “and”
• → means “yield”
States of Matter
• Products and reactants in chemical
reactions are present in different states
• Solid (s)
• Liquid (l)
• Gas (g)
• Aqueous (aq)- dissolved in water
• Precipitate (ppt)- solid product of a
reaction
Practice- what is formula equation?
Solid magnesium and aqueous Aluminum
Chloride react to form an Aluminum
precipitate and aqueous Magnesium
Chloride
Practice- what is the formula
equation?
aqueous sodium chloride reacts with
aqueous lead (II) nitrate to yield a lead (II)
chloride precipitate and aqueous sodium
nitrate
• Solid Potassium metal and chlorine gas
combine to form aqueous potassium
chloride.
Aluminum and liquid hydrochloric acid
(HCl) react to form Solid aluminum
chloride and hydrogen gas.
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
Mg(s) + O2(g)  2MgO
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
Na(s) + O2(g)  Na2O(s)
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
2Al(s) + Cl2(g)  Al2Cl3(s)
Is this chemical equation balanced? Defend
you answer and how it relates to the Law of
Conservation of Mass.
Br2 + O2  2Br2O
Remastery quiz
• Work silently and alone for full credit
Warm Up
1. When pressure increases, what happens
to volume?
2. When temperature increases, what
happens to volume?
Conclusions
• Pay attention
• Remember: CAUSE → EFFECT
• Lines intersecting on a graph means the
values are equal at that point
• It’s all about relationships!
Conclusions
Incubation Temperature of Turtle Eggs Versus Sex of Hatchlings
Four
groups
of 25
eggs
Group 1
Temperature Number of
Males
Number of Eggs not
Females
hatched
26
21
2
2
Group 2
28
13
11
1
Group 3
30
1
19
5
Group 4
32
1
20
4
Remastery quiz
• Work silently and alone for full credit
Gases
• Particles are:
–
–
–
–
Spread apart
In constant motion
Very small
Exert force on each other
when collide
– Exert force on container
when collide
– Which is the gas?
Volume
• Volume measures how much space
matter takes up.
• The units of Volume are Liters (L)
– 1 L = 1000 mL
Pressure
• Pressure describes how
much force is applied over
an area.
– The more force, the more
pressure.
– The more area, the less
pressure
• Why doesn’t this person
have a lot
of holes in their body?
Gas Pressure
• Gas Pressure is a measure of how much
force the gas molecules hit the container
with.
– If the gas molecules hit the container harder, what
will happen to the pressure?
• Answer in complete sentences
Units of Pressure
• Pressure is measured in many different
units.
– Atmospheres (atm)
– Kilopascals (kPa)
– Millimeters of Mercury (mm Hg)
– Torr (torr)
• 1 atm = 101.3 kPa = 760 mm Hg = 760
torr
Pressure and Volume
• Recall:
– Pressure is related to the force on the gas molecules
in the container
– Volume is how much space the gas takes up
• Imagine a balloon.
– If the pressure on the gas molecules increases what
do you think will happen to the volume the gas
molecules take up?
• Explain your answer on the sheet in complete
sentences
Boyle’s Law
• Boyle’s Law relates gas pressure and gas
volume
• Equation:
P1V1  P2V2
Initial Pressure
Initial Volume
Final Pressure
Final Volume
*You can use any units, as long as they are on the same on each side
Temperature
• Temperature is a measure of how fast the
molecules in a substance are moving.
– The faster they move, the higher the temperature
• Temperature is measured in:
– Degrees Fahrenheit (°F)
– Degrees Celsius (°C)
– Kelvin (K)
Charles’ Law
• Charles’ Law relates the temperature of a gas
to the volume of a gas.
Initial Volume
Initial Temperature
V1 V2

T1 T2
Final Volume
Final Temperature
• The units for T must be Kelvin (K).
– What could happen if the temperature was in C or F?
• The units for volume can change.
Remastery quiz
• Work silently and alone for full credit
Significant figures
• A way of keeping track of the precision of
a measurement
Significant figures
• All measured digits + 1 guessed digit
What’s the measurement?
• Graduated cylinder- measure from the
bottom of the curve
What’s the measurement?
• Triple beam balance- add three levels
together
How many sig figs?
• Graduated cylinder- measure from the
bottom of the curve
How many sig figs?
• Triple beam balance- add three levels
together
How many sig figures?
•
•
•
•
•
•
400000
.000034
.00201
3402
60001
4032.00
Remastery quiz
• Work silently and alone for full credit
Warm Up
1. What is the purpose of multiple trials?
2. Which of the following conducts
electricity in water: NaCl or C2H3O2
Multiple Trials
• Doing an experiment multiple times or
having multiple subjects
• Necessary to reduce error by taking the
average
• Need a trial that has the control group
(original form)
Remastery quiz
• Work silently and alone for full credit
With addition of solute
• Boiling point increases
• Freezing point decreases
Why?
• Explain, in complete sentences, why
people add salt to water to make the pasta
cook faster.
• Explain, in complete sentences, why salt is
added to roads when it snows.
BP and FP Change Equation
T  kmi
Change in temperature
Number of dissolved particles
constant
molality
kb for water is 0.51 °C/m
kf for water is -1.86 °C/m
mol
m
kg
An Example
• What is the boiling point of a 0.75 m MgF2
if water is the solvent?
Practice Questions
Question #1
Question #2
• Which of the
following will
increase the boiling
point of solvent the
most?
• What is the
freezing point of a
salt (NaCl) water
solution with a
molality of 3 m?
–
–
–
–
–
1 m NaCl
1 m C12H22O11
1 m CaCl2
1 m Al2O3
1 m MgO
More Practice
Practice Quietly
by yourself. Raise
you hand if you
have a question
• What is the molarity of a solution with 2.0 moles of CaCl2 in
4 L of H2O?
• What is the molality of a solution with 4.0 moles of CaCl2 in
6 L of H2O?
• What is the boiling point of a solution with 4 m CaCl2 in
water?
Remastery quiz
• Work silently and alone for full credit
Conductivity
• When ions are dissolved in water, they can
conduct electricity
– Because they can move charges in the liquid
• Why can’t ionic compounds conduct
electricity while they are solids?
• Why can’t covalent compounds dissolved
in water conduct electricity?
Review: ionic compound
A METAL + A NONMETAL
Why do some ionic compounds
conduct better?
• More ions per volume of solution
(concentration) means more charge is
carried (better conduction)
• Ionic compounds that create more ions
(higher concentration) when dissolved
conduct electricity better
REMEMBER: Dissolution
• Dissolution is when an ionic compound
dissolved into ions in a polar solvent.
– How many ion (not particles) will the following
compounds make?
• NaCl
• CaCl2
• CH3OH
2
3
none
Practice Problems
Question #1
Question #2
• Which of the
following will
conduct
electricity?
• In complete
sentences, explain
why gatorade and
powerade can
conduct electricity.
– Pure water
– Salt water
– A pile of salt
– Sugar water
– A pile of sugar
Practice
•
•
•
•
•
•
•
•
NaCl
H2O
H2O with dissolved ions
C2H6O3
MgCl2
Strong electrolyte
Weak electrolyte
Solutions with high concentration of dissolved
ions
Remastery quiz
• Work silently and alone for full credit