Transcript Matter - kingdomschools

Chemical Building
Blocks
Chapter 1.1 –
Describing Matter
Key Terms








Matter
Chemistry
Substance
Physical Property
Chemical Property
Element
Atom
Chemical Bond







Molecule
Compound
Chemical Formula
Mixture
Heterogeneous Mixture
Homogeneous Mixture
Solution
Matter


Matter is anything that takes up space and
has mass
Most things we think of as “stuff” is matter








Air
Plastic
Metal
Wood
Glass
Paper
Cloth
People
Not matter?

With all of those things as matter, what isn’t
matter?






Light
Sound
Emotions
Electricity
Force
For now, we’re not going to focus on notmatter.
Properties of Matter

Matter can have many different properties.



Plastic has different properties than paper, or air.
Can be hard, soft, rough, smooth, hot or cold,
liquid, solid or gas. Some catch fire easily, while
others won’t burn.
Chemistry is the study of the properties of
matter and how matter changes.
Substances



The properties of matter depends on its
makeup.
Some types of matter are called substances,
while others are not.
A substance will always have a particular
makeup (called composition), and will always
have a particular set of properties.



Salt always has the same properties and
composition, no matter where we find it.
From seawater or a salt mine, all the same.
On the other hand, think about a blueberry
muffin. Some muffins are sweeter than
others, some are more salty, or drier.
Blueberry muffins are NOT a substance,
because not always made up of the same
composition. What goes into it can change
amounts.
Every form of matter has two kind of
properties, physical properties and
chemical properties.

Physical Properties







Something that can be
observed without changing
a substance into another
substance.
Freezing point
Melting point
Color
Density
Dissolves in water
Used to identify substance

Metals

Chemical Properties


Describes how the
substance can change into
another substance
To be observed, must
attempt to change it into
another substance



Methane burns
Iron rusts when exposed
to oxygen
Bread dough to produce
gas from yeast
Elements




Elements are the basic building block of
matter
An element is a pure substance that cannot
be broken down into any other substance by
chemical or physical means.
Elements are the simplest substances
Each element can be identified by its specific
physical and chemical properties

Familiar elements





Aluminum foil
Inside of pennies is zinc
Outside of pennies is copper
Oxygen, and nitrogen gas in the air we breath
Elements are often represented by a one- or
two-letter symbol

Such as C for carbon, O for oxygen, N for
nitrogen






Since the most simple substances, what is the most
basic form of an element?
The atom.
The atom is the basic particle from which all
elements are made.
Different elements have different properties,
because their atoms are different.
Atom comes from the Greek term meaning
indivisible.
We’ll learn more about atoms later.
When Atoms Attack!




Well, not really. But they combine.
When atoms combine, they form a chemical
bond, which is a force of attraction between
two atoms.
In many cases, atoms combine to form larger
particles called molecules, which are groups
of two or more atoms held together by
chemical bonds.
Can be same elements or different elements
Compounds



All matter is made of elements, but most
elements found in nature are combined with
other elements.
A compound is a substance made of two or
more different elements chemically combined
in a set ratio.
This combination in a set ratio can be
described by a chemical formula, which
shows which elements are in the compound,
and their ratio.

Example: The gas we exhale is carbon
dioxide.




Represented by formula of CO2
Shows one molecule of the compound of carbon
dioxide contains 1 carbon for every 2 oxygen.
Small number to right of symbol indicates number
of atoms of the element.
If ratio is different, you have a different
compound.

H2O vs. H2O2

When elements combine to form a
compound, the compound will have
properties different from the elements it is
made from.


Sodium, chlorine and salt
Carbon, hydrogen and oxygen to make sugar
Mixtures




If not a substance, but still matter, is a
mixture.
A mixture is made of two or more
substances (elements, compounds or both)
that are together in the same place but NOT
chemically combined.
Each substance in a mixture keeps individual
properties
Parts of mixture not combined in a set ratio

Two types of mixtures

Heterogeneous mixture



Can see different parts to it
Soil, salad
Homogeneous mixture



Parts evenly mixed so you can’t see different parts
Salt water, kool-aid, air (clean)
Solution is formed when substances are dissolved


Sugar water
Brass (copper and zinc)
Separating Mixtures

One of the other differences between
mixtures and compound is you cannot
PHYSICALLY separate a compound, but
you can PHYSICALLY separate a mixture.
Chemical Building
Blocks
Chapter 1.2 –
Measuring Matter
Measuring Matter


We use LOTS of different methods to
measure the matter around us
We commonly use



Weight and mass
Volume
Density
Vocabulary





Weight
Mass
International System of Units
Volume
Density
Weight and Mass

Weight




How would you find your weight?
Would it read the same if you were underwater?
If you were on the moon?
Weight is the measure of the force of gravity on
you.


Which is why it would be different on the moon,
different force of gravity.
On moon, 1/6 force of gravity, so only 1/6 your weight!
Chemical Building
Blocks
Chapter 1.2 –
Measuring Matter
Measuring Matter


We use LOTS of different methods to
measure the matter around us
We commonly use



Weight and mass
Volume
Density
Vocabulary





Weight
Mass
International System of Units
Volume
Density
Weight and Mass

Weight




How would you find your weight?
Would it read the same if you were underwater?
If you were on the moon?
Weight is the measure of the force of gravity on
you.


Which is why it would be different on the moon,
different force of gravity.
On moon, 1/6 force of gravity, so only 1/6 your weight!

Mass






Different from weight, but related.
The force of gravity on you (weight) is based
partially on your mass.
Mass is the measurement of the amount of matter
in the object.
If you travel to the moon, does the amount of
matter in you change? Would your mass
change?
Unlike weight, mass DOES NOT change with
location, even when the force of gravity
changes.
The mass of an object is a physical property.
Units of mass



Almost everything in science has units, and we need
to remember them.
Mars Lander story.
To unify units, scientists use a system called the
International System of Units.




Abbreviated SI, after its French name.
SI unit of mass is the kilogram (kg)
About 1kg per 2 pounds.
Can also use gram (g), which is 1/1000 of a kg.
Volume


Volume is the amount of space that
something takes up.
Common units of volume include the liter (L),
milliliter (mL), and cubic centimeter (cm3).

Interesting note: 1 mL = 1 cm3
Calculating Volume


A bit of math! Oh noes!
Finding volume for a rectangular object like a
brick is easy.


Volumerectangle = length x width x height
Volume of an irregular object a little harder

Find its volume by process called displacement
Volume Displacement
Density


Often confused with volume or surface area
Similarly, just because two things have the
same volume, not the same mass.


Empty bucket vs. bucket filled with concrete
Or, just because two things have the same
mass, not the same volume

1 kg of feathers takes up more space than 1 kg of
sand.



Density is an important property of matter
(physical property)
Density relates the mass of the object in a
given volume.
Often, expressed as number of grams in a
given cubic centimeter.


Water has density (at room temperature) of one
gram per cubic centimeter (1g/cm3).
This means that if I have one cubic centimeter of
water, it would have a mass of 1 gram.
Volume w/ Math!


Can be expressed
Density
mathematically as
Example problem: A
small block of wood
floats on water. It has
a mass of 200g and a
volume of 250cm3.
What is the density of
the wood?
Mass

Volume
Mass
Density 
Volume
Giving us an answer of:
200 g Density  0.8g / cm3
Density 
Volume
200 g
Density 
3
250cm
Sink or Float?



Why do certain things sink and why do they
float?
Density!
Take water for example:



Objects less dense than water will float
Objects more dense than water will sink
Why do helium balloons float?
Chemical Building
Blocks
Chapter 1.3 –
Changes in Matter
Section 3 Vocabulary








Physical change
Chemical change
Law of conservation of mass
Energy
Temperature
Thermal energy
Endothermic change
Exothermic change
Changes in Matter




Chemistry is mostly the study of the changes
in matter.
Different ways matter can change
Everything from building a sand-sculpture to
receiving a sunburn can be a change in
matter.
There are different TYPES of changes in
matter however.
Physical Changes



A physical change is any change that alters
the form or appearance of matter but does
not make any substance in the matter into a
different substance.
In other words, a substance that undergoes a
physical change is still the same substance
after the change.
Examples?
Major Physical Changes

Changes of State





Changing from solid, liquid or gas.
Water evaporating
Ice melting
Dry ice turning into gas
Changes in Shape or Form


Dissolving something
Bending, crushing, breaking, chopping, etc.
Chemical Changes



A chemical change, or chemical reaction, is
a change in matter that produces one or
more new substances that weren’t there
before.
To simplify, creates new substances with
different properties from the original
substances.
Examples?
Major Examples of Chemical
Change



Combustion (burning) produces heat, light,
and new substance
Electrolysis breaks compounds into elements
or simpler compounds
Oxidation is when a substance combines with
oxygen slowly (rusting is an example)
Conservation of Mass




One of the basic laws of chemistry.
If you measure carefully, the amount of mass
(measure of amount of matter) does not
change when a chemical change occurs.
Meaning, no mass is gained or lost during a
chemical reaction. Always same amount of
mass.
Mass just changes form.
Matter and Thermal Energy



We’ll talk more about this later in the year.
Energy is the ability to cause change.
Every chemical or physical change requires a
change in energy.




Bending a paper clip requires energy
Ice melting absorbs energy from the surrounding
matter
Ice freezing releases energy into the surrounding
matter.
Candle wax burning releases energy.
Temperature and Thermal
Energy


Hot and cold are not useful, we use actual
temperature.
Temperature is the measure of the average
energy of particles of matter.


More energy = higher temperature
Thermal Energy is the total energy of all the
particles in an object.

Related to temperature, but not the same.
Thermal Energy and Changes
in Matter



When matter changes, the most common
form of energy released or absorbed is
thermal energy.
If energy is released by the change, is called
an exothermic change.
If energy is absorbed during the change, is
called an endothermic change.
Chemical Building
Blocks
Chapter 1.4 –
Energy and Matter
Vocabulary





Kinetic energy
Potential energy
Chemical energy
Electromagnetic energy
Electrical energy
Forms of Energy


Like matter, energy is never destroyed, it just
changes form.
When energy is transformed, it just changes
from one form of energy into another.
Kinetic & Potential Energy

Kinetic energy is the energy of matter in motion.



Anything moving has kinetic energy
How can something moving cause change?
Potential Energy is the energy of an object due to
its position.



Stretching a rubber band back increases its potential
energy.
Rolling a ball to the top of a hill increases its potential
energy.
How can this cause change?
Chemical Energy


Chemical energy is a form of potential
energy that is stored in the chemical bonds
that holds atoms together.
When a chemical change occurs, these
bonds are broken, and new bonds form.



Sometimes this releases energy, sometimes it
absorbs energy.
This energy form is usually thermal energy.
Gummy bear demonstration.
Electromagnetic Energy



A form of energy that travels through space
as waves.
Visible light is an example of this.
Radio waves are examples of this.
Electrical Energy


Electrical energy is the energy of electrically
charged particles moving from one place to
another.
During many chemical changes, electrons
move from one place to another.
Transforming Energy


During a chemical change, chemical energy
may be changed to other forms of energy.
Other forms of energy may also be changed
to chemical energy.
Movement example.