Transcript Unit 1 Properties off Matter 2016-17

Unit 1 Properties off
Matter
Mrs. Ayyad
Chapter Summary: Key Points
1
The Scientific Method
States of Matter
Substances
Mixtures
Physical Properties
Chemical Properties
Extensive and Intensive Properties
SI Base Units
Mass
Temperature
Volume and Density
Significant Figures
How Matter is Classified?
 Atoms:
the smallest unit of an element that
maintains the properties of that element.
 Elements: are pure substances that contain
one kind of atom.
 Molecule : consists of two or more atoms
combined in definite ratios.
 Compound: 2 or more atoms that are different
combined together.
https://www.youtube.com/watch?v=0gsrW0Vb5sw
Atomic Structure
There are two basic components in every atom:
Electron Cloud
Nucleus
Subatomic Particles
Three subatomic particles make up every atom:
Subatomic Particle
Charge
Location
Proton
Positive (+)
Nucleus or “Core”
Neutron
No Charge (0)
Nucleus or “Core”
Electron
Negative (-)
Electron Cloud
What's an Element?
How to write an Element
Isotopes
 Atoms
of the same element with different
mass numbers.
• Nuclear symbol:
Mass #
12
Atomic #
6
• Hyphen notation: carbon-12
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
C
17
Cl
Isotopes

37
Chlorine-37
 atomic
 mass
#:
17
#:
37
#
of protons:
#
of electrons: 17
#
of neutrons: 20
17
37
17
Cl
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Average Atomic Mass
 weighted
 on
average of all isotopes
the Periodic Table
 round
to 2 decimal places
Avg.
(mass)(%) + (mass)(%)
Atomic =
100
Mass
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Average Atomic Mass

Calculate the avg. atomic mass of oxygen if
its abundance in nature is 99.76% 16O, 0.04%
17O, and 0.20% 18O.
EX:
Avg.
Atomic
Mass
(16)(99.76) + (17)(0.04) + (18)(0.20)
=
100
Amu- Atomic mass
unit
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
= 16.00
amu
Answer Worksheet
Classification of Matter
A mixture can be separated by physical means into its components
without changing the identities of the components.
Classification of Matter
Solids do not conform
to the shape of their
container.
Solid particles are held
closely together in an
ordered fashion.
Liquids do conform to
the shape of their
container.
Liquid particles are close
together but are not held
rigidly in position.
Gases assume both the
shape and volume of
their container.
Gas particles have
significant separation
from each other and
move freely.
Three states of matter
At room temperature most substances exist in one of three
physical states.
solid
liquid
gas
Solids
 The
particles in a solid are very tightly
packed and vibrate in place.
 Solids
have a definite volume and shape.
Particles in a solid – animation
Liquids
 The
Picture was
taken at the
exact
moment
these water
balloons
were
popped!
particles in a liquid are close
together but can move and flow past
one another.
 Liquids
have a definite volume but
they do not have a definite shape.
This is why liquids like water take the
shape of the container they are in.
Particles in a liquid – animation
Gases

Particles in a gas have higher amounts of energy than those in a
solid or liquid.

Gases do not have a definite shape or volume. When placed in a
container, it fills up the entire container and spreads out as far as
possible.
Particles in a gas – animation
Molecular Motion
Adding heat
Removing heat
The Properties of Matter
There are two general types of properties of matter:
1) Quantitative properties are measured and
expressed with a number.
2) Qualitative properties do not require
measurement and are usually based on
observation.
The Properties of Matter
A physical property is one that can be observed
and measured without changing the identity of the
substance.
Examples: color, melting point, boiling point
A physical change is one in which the state of
matter changes, but the identity of the matter does
not change.
Examples: changes of state (melting, freezing,
condensation)
The Properties of Matter
A chemical property is one a substance exhibits as
it interacts with another substance.
Examples: flammability, corrosiveness
A chemical change is one that results in a change
of composition; the original substances no longer
exist.
Examples: digestion, combustion, oxidation
The Properties of Matter
An Extensive property depends on the amount of
matter.
 Examples: mass, volume
An Intensive property does not depend on the amount
of matter.
 Examples: temperature, density
Temperature
There are two temperature scales used in chemistry:
The Celsius scale (°C)
 Freezing point (pure water): 0°C
 Boiling point (pure water): 100°C
The Kelvin scale (K)
 The “absolute” scale
 Lowest possible temperature: 0 K (absolute zero)
K = °C + 273
Temperature
The Fahrenheit scale is common in the United States.
 Freezing point (pure water): 32°C
 Boiling point (pure water): 212°C
There are 180 degrees between freezing and boiling in Fahrenheit
(212°F-32°F) but only 100 degrees in Celsius (100°C-0°C).
 The size of a degree on the Fahrenheit scale is only 9 of a
5
degree on the Celsius scale.
9
Temp in °F = ( ×temp in °C ) + 32°F
5
Density
Typicall the units are g/ mL or g/ cm3
density =
mass
volume
d=
m
V
A piece of platinum metal with a density of 21.5 g/cm3 has a volume of
4.49 cm3. What is its mass?
d=
m
V
m=dxV
= 21.5 g/cm3 x 4.49 cm3 = 96.5 g
Taylor 2010
Density
A piece of metal with a mass of 114 g was placed into
a graduated cylinder that contained 25.00 mL of
water, raising the water level to 42.50 mL. What is
the density of the metal?
Ans: D
A.
B.
C.
D.
E.
0.154 g/mL
0.592 g/mL
2.68 g/mL
6.51 g/mL
7.25 g/mL
Taylor 2010
Accuracy and Precision
Good accuracy and good precision
Accuracy tells us how close a
measurement is to the true
value.
Precision tells us how close a
series of replicate measurements
are to one another.
Poor accuracy but good precision
Poor accuracy and poor precision
Day 2 Scientist
Democritus
(460 BC – 370 BC)



Proposed an Atomic Theory (along
with his mentor Leucippus)
which states that all atoms are
small, hard, indivisible and
indestructible particles made of a
single material formed into
different shapes and sizes.
Aristotle did not support his atomic
theory
Image taken from: https://reichchemistry.wikispaces.com/T.+Glenn+
Time+Line+Project
Antoine Lavoisier
(1743 – 1794)







Image taken from:
www.ldeo.columbia.edu/.../v1001/geo
time2.html
Known as the “Father of Modern Chemistry”
Was the first person to generate a list of
thirty-three elements in his textbook
Devised the metric system
Was married to a 13-year old Marie-Anne
Pierette Paulze; she assisted him with much
of his work
Was a tax-collector that was consequently
guillotined during the French Revolution
Discovered/proposed that combustion
occurs when oxygen combines with other
elements
Discovered/proposed the Law of
Conservation of Mass (or Matter) which
states, in a chemical reaction, matter is
neither created nor destroyed
John Dalton
(1766 – 1844)




In 1803, proposed an Atomic Theory
which states:
o All substances are made of atoms;
atoms are small particles that
cannot be created, divided, or
destroyed.
o Atoms of the same element are
exactly alike, and atoms of
different elements are different
o Atoms join with other atoms to
make new substances
Calculated the atomic weights of many
various elements
Was a teacher at a very young age
Was color blind
Image taken from:
chemistry.about.com/.../JohnDalton.htm
Atomic Theory Timeline
Scientist
John
Dalton
Information
All matter is made of atoms.
Atoms are too small to see,
indivisible and indestructible.
All atoms of a given element
are identical.
Model
J.J. Thomson
(1856 – 1940)

Proved that an atom can be divided
into smaller parts

While experimenting with cathoderay tubes, discovered corpuscles,
which were later called electrons

Stated that the atom is neutral

In 1897, proposed the Plum Pudding
Model which states that atoms
mostly consist of positively charged
material with negatively charged
particles (electrons) located
throughout the positive material

Won a Nobel Prize
Image taken from:
www.wired.com/.../news/2008/04/d
ayintech_0430
Atomic Theory Timeline
Scientist
J.J
Thompson
Information
Discovered the negative
electron, and predicted
that there also must be a
positive particle to hold
the electrons in place.
Model
Atomic Theory Timeline
Scientist
Information
Ernest
Rutherford
Discovered the nucleus
of an atom and named
the positive particles in
the nucleus “protons”.
Concluded that electrons
are scattered in empty
space around the
nucleus.
Model
Atomic Theory Timeline
Neutrons
Scientist
James
Chadwick
Information
Discovered that neutrons were also
located in the nucleus of an atoms
and that they contain no charge.
Model
Atomic Theory Timeline
Scientist
Neils Bohr
Information
Concluded that electrons are
located in planet-like orbits
around the nucleus in certain
energy levels.
Model
http://www.brainpop.com/science/matterandchemistry/atomicmodel/
The Law of
Conservation
of Mass
We’ve talked about changes
in matter…

The evaporation of a puddle of water

Rust forming on a metal fence
The Law of
Conservation of Mass
 During
a chemical reaction, matter
cannot be created or destroyed.
 Even
though the matter may change
from one form to another, the same
number of atoms exists before and
after the change takes place!
Open System

There is exchange of matter and energy with surroundings
•
Mass is lost to the environment; once gone,
that mass cannot be measured.
•
Example: Burning Wood
Closed System

No matter can enter/leave the system only energy
An Example of the Closed System.

Test tube containing lead nitrate is
placed upright in a flask that contains
potassium iodide.

What are these?


REACTANTS!
They don’t mix!

A stopper is put in place to create a closed system – an environment
where matter cannot enter or escape.

The mass of the system is found.

After the mass is found, the system is turned upside down so the lead
nitrate can mix with the potassium iodide.

They create lead iodide and potassium nitrate.
Although
the matter changed in
form, the total mass of the
system remains unchanged.
When iron reacts with oxygen in
the air, they form rust or IRON
OXIDE.
This
is written as:
Iron + Oxygen
Iron Oxide
TAKE A
LOOK AT
THE
NUMBERS
O2
Fe
Fe
How many Iron
molecules?
Fe2O3
O2
O2
How many
Oxygen
molecules?
What about
the
PRODUCT?
3 Kinds of Variables
 Independent
Variable – something
that is changed by the scientist
What
is tested
What
is manipulated
Variables

https://www.youtube.com/watch?v=x2606GQmDqY