Living in the Environment
Matter and Energy
The Nature of Science
Ask a question
and collect data
to explain data
In data become
Ask a question
and collect data
to explain data
In data become
What is Science
and What Do Scientists do?
Science is an attempt to discover order
in the natural world and use that to
Scientists collect data, form
hypotheses, and develop theories,
models and laws about how nature
Models and Behaviour of Systems
Scientists use models or simulations to find out how systems
work and to evaluate ideas or hypothesis.
A system is a set of components that function
in some regular manner.
have key components
Inputs (from the environment
matter, energy or information
throughputs within the
system at certain rates
Outputs (to environment)
What types of matter do we find in nature?
Matter is anything that has mass and takes up space.
Matter has two forms:
1. Elements: building blocks of matter.
2. Compounds: 2 or more elements held together by
Chemists use symbols: e.g. Carbon (C), Oxygen (O),
Building Blocks of Matter
Atom: The smallest unit of matter.
Ion: An electrically charged atom/atoms
Molecule: A combination of two or more atoms of
the same or different elements.
In nature we find molecules. For example nitrogen (N
and oxygen (O
) are found in air.
Here 2 is number of Atoms.
1. Protons (positively charged)
2. Neutrons (uncharged)
3. Electron (negatively charged)
of the atom is Nucleus.
Equal number of protons and
Each element has a specific atomic number.
Atomic number is equal to number of protons in the nucleus.
H=1, C=6, U=92
An atom is made up of a cloud of electrons that surrounds a nucleus
containing protons and (in most cases) neutrons.
Most of the mass of an atom is concentrated in the nucleus. So
Atomic Mass= P+N in its nucleus.
Examples of Isotopes
Different isotopes of an
element have different
with different Neutron
Atomic Mass= P+N
Atoms of some elements can lose or gain electrons to form ions.
Metals: Electron givers
metals: Electron receivers
ions in a solution are a measure of how acidic or basic it is.
The pH of a solution is a measure of its concentration of
hydrogen ions (H
Neutral pH is 7; acid solutions are below 7;
and basic solutions are above 7.
Chemical formulas of a compound
Chemical formulas are a type of shorthand to show the type
and number of atoms/ions in a compound.
Each element in the compound is represented by a
symbol: H = hydrogen, N = nitrogen.
Subscripts show the number of atoms/ions in the
Ionic compounds are made up of oppositely charged
ions, (Na+ and
Compounds made of uncharged atoms are called
covalent (or molecular) compounds (CH
Organic compounds contain
combined with one another and with
various other atoms. Only methane (CH
has one carbon atom.
Hydrocarbons: compounds of carbon and
Chlorinated hydrocarbons: compounds of
carbon, hydrogen, and chlorine atoms.
Simple carbohydrates: specific types of
compounds of carbon, hydrogen, and
1 atom carbon
4 atoms hydrogen
All compounds without the combination of carbon atoms
and hydrogen atoms and/or
other elements’ atoms are
Water, Carbon monoxide,
Carbon Dioxide, Ammonia
Matter exists in four states:
solid, liquid, and gaseous
physical states and a fourth state known as
1.Water exists as ice, liquid, or water vapor depending on its
2.Plasma is a high
energy mixture of positively charged ions
and negatively charged electrons. It is the most abundant
form of matter in the universe, but very little is found on
Heating a gas may
its molecules or atoms
(reducing or increasing the number of
thus turning it into a plasma, which
3. Scientists make artificial plasmas in fluorescent light, arc
lamps, neon signs, gas discharge lasers, and TV and
Four States of Matter
Energy is the capacity to do work and transfer heat; it
has mass and speed; wind and
electricity are examples.
2. Potential energy
is stored energy, ready to be used: an
unlit match, for example.
Potential energy can be changed to kinetic energy: drop
an object, for example.
Electromagnetic radiation is energy that travels as a wave, a result of
changing electric and magnetic fields.
has a different
wavelength and energy content.
Travels through space at speed of
electromagnetic spectrum describes the range of electromagnetic
waves that have different wavelengths and energy content
:energy to knock electron out and form positive ion. Harmful
is the total kinetic energy of all moving atoms, ions, or
molecules in a substance.
It can be transferred from one place to another
conduction, and radiation.
is the average speed of motion of atoms, ions, or
molecules in a sample of matter.
is measured by its usefulness. High energy is
concentrated and has high usefulness
.(electricity, chem. Energy
stored in gas, coal, conc. Sunlight)
Low energy is dispersed and
can do little work
.(heat stored in oceans, atmosphere)
Heat and Temperature
When matter has
a physical change
, its chemical composition is
not changed; the molecules are organized in different
.(ice to water)
, the chemical composition of the
elements/compounds change. Shorthand chemical equations
represent what happens in the
reaction.(burning coal + O2 =
The Law of Conservation of Matter states that no atoms are
created/destroyed during a physical or chemical change. The
same is true for energy.
1. Atoms are rearranged into different patterns/combinations.
2. Atoms can have physical or chemical changes, but they are
never created nor destroyed
“Everything we think we have thrown away is still here with us
in one form or another”
The Law of Conservation of Matter
Chemical equations are used to verify that no atoms are created or
destroyed in a chemical reaction.
The number of atoms on one side of the equation must equal the
number of atoms on the other side of the equation.
9 p. 44
We will always have some pollutants, but we can
produce less and clean up some that we do
Three factors determine the severity of a pollutant’s
chemical nature, concentration, and
persistence (how long it stays in the air, water, soil,
Dilution of concentration of a pollutant is only a
Pollutants are classified into four categories based
degradable, biodegradable, slowly
degradable, and non
measures the amount of useful work by
a specific input of energy. Overall, energy efficiency is very poor
about 16% of energy produces useful work.
41% is unavoidable waste energy, and 43% is unnecessarily wasted
A change in habits can further reduce this waste
Energy Laws: Two Rules We Cannot Break
The First Law of Thermodynamics
states that energy can neither be
created nor destroyed, but can be converted from one form to
The Second Law of Thermodynamics
states that when energy is
changed from one form to another, there is always less usable
In changing forms of energy, there is a loss
in energy quality
is often produced and lost.
In living systems, solar energy is changed to chemical energy, then to
mechanical energy. High quality energy degrades to low quality
less useful energy.
We can never recycle high energy to perform work.
Resource use automatically adds some waste heat/waste matter
to the environment.
Advanced industrialized countries have
Resources flow into planetary sinks (air, water, soil, organisms)
with accumulation to harmful levels.
Eventually consumption will exceed capacity of the
environment to dilute/degrade
wastes and absorb waste heat.
Recycling/reusing more of Earth’s matter resources
of nonrenewable resources and reduces environmental impact.
Shifting to a more sustainable,
) , matter
economy is the best long
term solution to
Still uses high energy but buys us time.
Waste less matter; live more simply; and slow population growth.
Energy Laws and Environmental Problems