Observation of a Candle Lab
!
Observation of a Candle Lab
What were some chemical and physical
changes you observed?
! Melting
!
Does the candle wax burn as a solid,
liquid or vapor?
of wax – chemical or physical?
–
! Wax
turning to vapor?
! Wick
burning?
Procedure #4
Discussion of solid-liquid-gas transition…and that the vapor of the blown-out candle was relit by the 2nd candle…without touching the wick of the
blown-out candle (maybe draw pictures)
Observation of a Candle Lab
Observation of a Candle Lab
What is combustion?
What does a combustion reaction require?
!
!
1.
Fuel: The thing you are burning
2.
Ignition: Spark or heat
3.
Oxygen: O2 in the air
!
What are the products of combustion?
Candle wax + O2 "
CO2 + H2O
Test in step #8 & #9:
Ca(OH)2 + CO2 "
CaCO3 + H2O
Condensation in step #6
Wire Gauze Experiment
!
Wire Gauze Experiment
!
Metal is a conductor
Wire Gauze
HEAT
Explain why Sir
Humphry Davy invented
a safety lamp for miners
where a flame was
covered by a wire
gauze?
http://www.staffspasttrack.org.uk/
exhibit/coal/images/
safetyandrescue/
PM1davylamp.jpg
Observation of a Candle Lab
!
Why did the water rise into the flask?
–
O2 was consumed by the fire
–
when the fire goes out the air in the flask
What is matter?
cools and condenses (shrinks)
–
Creates vacuum so the water is sucked in.
Reading Guide Part One #2
Matter …anything that has
!
Mass
–
–
–
!
Reading Guide Part One #1,2
Matter or Not Matter?
SI units: g or kg
Measured w/ balance
Not the same as weight
Volume (takes up space)
–
–
SI units: cm3 or mL
Measurement:
! Ruler
(How?)
cylinder (2 ways)
! Graduated
Reading Guide Part One #2
Reading Guide Part One #1,2
Is it matter, or not?
!
!
Even though some objects have a very
small mass or take up very little space
(small volume) they are still MATTER!
“Can I fill a container with it?”
Other things that are not matter:
!
What are some things you listed that are NOT
matter?
–
–
–
–
Gravity
Rainbows
Energy
Time
Reading Guide Part One #9, Part Two #6
Reading Guide Part One #8
Pure Substances
!
!
Pure Substances
Composed of one type of matter
Fixed composition
Pure Substances
Pure Substance
Elements
Compounds
Elements
Compounds
one type
atom
(Symbol)
atoms of two or more
elements
(Formula)
Mention here that Elements have one chemical symbol, compounds have two or more chemical symbols in their formulas
Reading Guide Part One #7
Reading Guide Part One #9, Part Two #7,8,9
Element or Compound
Remember…
!
The word “PURE” is sometimes used in a nonchemistry way…
!
In chemistry, PURE = element or compound
ONLY!
–
Aluminum, Al
Pure honey, Pure orange juice
Rust, Fe2O3
Sulfur, S
Sugar, C6H12O6
Water
Maybe mention here that each capitol letter is a new element (the second letter of an element’s symbol is always lower case.
Reading Guide Part One #10,12,13
Classification of Matter
Mixtures
!
Matter
Mixtures
Pure
Substances
Compounds
Elements
≥ 2 elements or compounds
– Components do not
share chemical bonds
– So they can be separated
by physical changes
using properties like
! Boiling Point
! Size (Filtering)
! Melting Point
! Magnetism
! Solubility
Draw a picture of Mg—O vs sand and water in a beaker
Sugar Water
Reading Guide Part One, #5, Part Two #1
Classification of Matter
Heterogeneous Mixtures
–
Matter
–
“different”
Can see/separate phases (macroscopic)
!
Mixtures
!
Pure Substances
–
Heterogeneous
Mixture
Compounds
Homogeneous
Mixture
Identify phases in these following heterogeneous
mixtures
!
Elements
What is a PHASE?
May require a microscope to distinguish phases
!
!
Soil
Seawater
Blood
Reading Guide Part One #5, Part Two, #2
Homogeneous Mixtures/Solutions
–
–
–
“Same”
One phase - looks the same throughout
Ex:
! Salt
–
water (completely dissolves)
Reading Guide Part Two, #3
Homogeneous Mixtures
!
Alloys (p. 23)
–
Solution of solids/metals
!
!
!
Bronze
Steel
Gold jewelry
A.K.A. = SOLUTIONS
! May
appear to be pure substances, but their
composition may vary
separate because particles are
submicropscopic (ions, molecules)
! Cannot
Reading Guide Part Two, #4,5
Solutions/Homogeneous Mixtures
!
Solute:
–
the thing or stuff that you are dissolving
!
Solvent:
!
Aqueous Solutions = water is the solvent
–
the substance you use to dissolve the solute
Chapter 1, Section 2
Properties and Changes of Matter
Reading Guide Part One #6, 13
Physical)Properties
• Observed)without)changing)the)chemical)
composition)of)the)substance
1. Qualitative
Reading Guide Part One #6
Quantitative)or)Qualitative
!
The quarterback threw a 35 yard pass
!
Water contains H and O
–
–
• Ex:)Solids)are)rigid
2.Quantitative
• Water’s)freezing)point)is)O)°)C
• )The)density)of)Fe)is)7.86)g/cm3
Quantitative
Qualitative
!
The ratio of hydrogen to oxygen in water is
2:1
!
The reaction produced five grams of a yellow
powder
–
–
Quantitative
Both?
26
Reading Guide 1.2 #3-6
States)of)Matter)–)Physical)Property)
• Boiling'point/'Condensation'point
• gas)#)")liquid
• Volatile:"liquid"easily"become"a"gas"a"
room"temperature
• Melting'point/Freezing'point
• solid)#)")liquid
• True)or)False?)Water)melts)and)freezes)at)
0°)C?
Reading Guide 1.2 #2
Chemical)or)Physical)Property?
!
!
!
!
!
!
!
!
!
Color
Flammability
Reactivity with acid
Mass
Magnetism
Density
Conductivity
Solubility
Decomposition in sunlight
How would
you define a
chemical
property?
28
Physical)Change
What)happens)in)a)chemical)
reaction/change?
• Changes)to)matter)that)do)not)alter)the)
composition
• Atoms)are)rearranged)to)make)NEW)
SUBSTANCES!!
• Breaking)glass
• Change)of)state)(solid,)liquid,)gas)
• Dissolving
• Crushing
• Don’t)create)or)destroy)anything…
• The)stuff)you)start)with)is)chemically'
different'from)the)stuff)at)the)end
• Chemical)reactions)are)very)difficult)or)
impossible)to)reverse.
Chemical)Reactions
Chemical)Reactions
• Bubbles)form)/)
Gas)Evolution
• Explosion
• light
• heat
• sound
Chemical)Reactions
Chemical)Reactions
• Unexpected)
Color)Change
• What)do)we)have)to)do)to)get)water?
H
• Solid)forms)
from)2)liquids)
(precipitate)
H
H
H
O
Chemical)Reactions
• We)have)to)break)old)
bonds)and)create))new)
chemical)bonds.
Conservation)of)Mass
• Mass)cannot)be)created)or)destroyed
• Must)account)for)every)atom)before)and)
after)the)reaction)is)complete
O
H
H
2)H2)+)O2)")2)H2O
H
H
H
O
H
O
H
H
O
H
H
H
O
H
O
O
H
H
Reactions)that)RELEASE))Energy
• EXOTHERMIC
• “EXO”)
• “THERM”
• Heat)is)a)product
• Feels)warm+
Reactions
and Energy
What)is)energy?
Reading Guide 1.2 #10
Exothermic
A fireplace
Reactions)that)ABSORB)Energy
• ENDOTHERMIC
• “ENDO”
• “THERM”
• Heat)is)a)reactant
• Feels)cold
What)types)of)energy)are)
absorbed)or)released?
• Heat
• Light
• Electricity
• Sound
• Energy)cannot)be)created)or)destroyed,)but)it)can)
change+forms!!!
Where is the energy
coming from?
Questions
• Name)something)that)is)not)matter)and)
explain)why?
• What)is)the)difference)between)a)
qualitative)and)quantitative)observation?
• Describe)how)a)homogeneous)and)
heterogeneous)mixture)look)different)
from)each)other.
42
Questions
Questions
• What)is)the)difference)between)a)solute)
and)solvent?
• What)are)the)units)for)measuring)mass?)
volume?
• How)is)separation)of)a)mixture)different)
from)separation)of)a)compound)into)its)
elements.
• What)are)the)things)you)need)to)make)
combustion)happen?
• How)many)carbon)and)oxygen)atoms)are)
in)carbon)dioxide?
43
Questions
• Name)3)chemical)changes
• Name)3)physical)changes
• Name)3)physical)properties
• Name)3)chemical)properties
45
• What)things)are)given)off)from)
combustion?
44