Chemistry - Menihek Jr High Science€¦ · Project Introduction Due at the end of Chemistry unit...
Transcript of Chemistry - Menihek Jr High Science€¦ · Project Introduction Due at the end of Chemistry unit...
Matter
■ anything that has mass and
takes up space (volume).
■ It can be in the form of a solid,
liquid or gas (States of Matter)
■ Determine Particle Arrangement of solids, liquids, and gases
from the video.
■ Bill Nye: Phases of Matter
Matter is made of Atoms
■ When all atoms that make up a
substance are the same, then that
substance is an element.
■ Elements are made of only one kind of
atom. Because of this, elements are
called "pure" substances.
■ An atom is the smallest piece of an
element that still has the properties of
that element.
Matter is made up of Elements.
■ Elements are substances that
contain one type of matter and
cannot be broken down or
separated into simpler
substances.
Example
The element aluminum is a lightweight, shiny
metal. If we took a piece of aluminum and cut
it into small pieces, it would still be aluminum.
Activity
Refer to the periodic table and locate the elements;
■ Aluminum
■ Tungsten
■ Gold
■ Titanium
■ Americium
■ Lead
Record the elements symbol
Record a fundamental use of each element (Text Pg 21)
Describing Matter
■ https://www.youtube.com/watch?v=8ta4HygRCpk
Describing Matter
#1. Physical Properties (Text Page 18)
■ Characteristics of matter that are often observed or measured.
■ Can be either qualitative (observed) or quantitative (measured).
Physical Properties of MatterQualitative Quantitative
State Solubility
Color Conductivity
Malleability Viscosity
Ductility Density
Texture Melting point
Magnetism Boiling point
lustre
Physical Properties & Physical Change
■ Characteristics that don’t
change the substance
■ no new substance formed
■ Ex: sugar dissolving in water
#2. Chemical Properties (Text Page19)
■ Observed when substances react with each other.
■ Determines a substances usefulness.
Chemical Properties & Chemical Change
■ Characteristics that change
the substance
■ A new substance is formed
Ex: Burning paper
■ Atoms of different elements can
combine to make new
substances.
■ If atoms combine that are of two
or more different elements, we
call that a compound.
Physical & Chemical Property Computer Lab
■ http://www.glencoe.com/sites/common_assets/science/virt
ual_labs/BL01/BL01.swf
Theory vs Law
■ A theory is less well supported
than a law.
■ Most laws are supported by
different and robust
experimental evidence.
Science Laws
■ Descriptions of events, patterns, or relationships that have
been observed over and over again.
■ Laws do not provide explanations, they simply state what
happens
Science Theories
■ Explanations of observations supported by evidence.
■ Theories may change as new facts become available. Laws
are constant.
Atomic Theory
■ The descriptions of matter and how it behaves.
■ Has undergone many modifications as new facts became available.
■ https://www.youtube.com/watch?v=thnDxFdkzZs
Early ideas... 2000 years ago
Empedocles:
■ matter was composed of four
“elements”; earth, air, water,
and fire.
Democritus
■ eventually a substance will be
cut into a piece that can no
longer be cut. He called this
piece atomos.
Development of Atomic Theory
■ John Dalton (1766-1844)
■ He suggested that the particles
that make up matter are like
small, hard spheres that are
different for different elements.
■ He defined an atom as the
smallest particle of an element.
Dalton’s Model... Billiard Ball Model
He believed atoms were small, hard spheres
like a billiard ball! (draw the ball)
J.J. Thomson (1856-1940)
■ He suggested that all atoms must contain electrons(negative charge).
■ His model pictured a positively charged ball with the negatively charged electrons embedded in it.
Ernest Rutherford (1871-1937)
■ He discovered that atoms have a nucleus.
■ two kinds of particles in the nucleus;
1. protons (positive charge)
2. neutrons (neutral)
Niels Bohr (1885-1962)
■ He proposed that electrons
surround the nucleus in
specific energy levels or shells.
■ Each electron has a particular
amount of energy.
■ Rutherford was able to develop Thomson’s model due to the development of new technologies. (gold foil experiment)
■ The development of cyclotrons and proton accelerators have further developed the model accepted today.
Atomic Number = • the number of protons in the nucleus.
It also represents the mass of the
protons. (amu)
• It also equals The number of electrons
surrounding the nucleus.
• All atoms are neutral in charge, so the
# of positive charges (protons) = the #
of negative charges (electrons)
Atomic Mass• The average mass of the atoms of an
element.
• Mass is the number of protons and
neutrons in an atom.
• # of neutrons = Mass number – atomic #
• Example: 7 – 3 = 4 neutrons.
Worksheet
■ Requires booklet and textbook page 50.
■ Review subatomic particles on the periodic table
■ Worksheet - Interpreting Atomic Theorists Models
Project Introduction
■ Due at the end of Chemistry unit (booklet 3)
■ Start researching ideas to complete a home experiment. (Video Project)
■ MythBusters: S13E05 - Do Try This At Home (FULL EPISODE) - YouTube
■ SciGuys:
– Elephant toothpaste: https://www.youtube.com/watch?v=-RRTnIGr6fg
– Rock Candy https://www.youtube.com/watch?v=VpOU0Fo7QfU
– Burning steel wool https://www.youtube.com/watch?v=nWdK1L7GXys
■
■ Ms. Dawe will go into more detail with you!