Download Science 9 Environmental Chemistry Chemicals in the Environment

Science 9
Environmental Chemistry
Chemicals in the Environment
 The environment is made up of chemicals that can support or harm living things:
◦ Essential Chemicals:
 Water
 Air
 Human activities can also cause chemical changes in the environment
 Recall that
are
cannot be broken down
 Chemicals are necessary for life but can also be harmful to the environment
which
 To constantly
the energy in an ecosystem, chemicals must
be
through living organisms and their environment.
 Nitrogen,
and
are the most
important elements recycled through organisms and their environment
The Nitrogen Cycle:
 Free nitrogen is converted (
) to form nitrogen compounds which are
then available to plants
 Lightning,
and
supply
nitrogen to plants which are then eaten by animals.
 Bacteria live in
with
.
Steps Recap:
Farmers and Nitrogen
The Carbon Cycle
 In the carbon cycle,
things and back to the environment
 Steps:
The Water Cycle:
passes from the environment into living
Pollution:
 Any
 Can be caused by
in the environment that is harmful to living things
or
processes.
Fertilizers:
 Natural or
 Numbers mean
potassium (sulfur)
 Example: 5-10-15
chemicals used in soils for plants to grow
of
,
What do these numbers really mean?
 Over-application can lead to environmental problems (crop damage,
etc.)
Pesticides:
 Pest = organism which harms people, crops or structures
 Herbicides
 Insecticides

Fungicides
 Improper use of
environment
DDT:
can be harmful to living things & the
,
Solid Wastes:
 Landfill and incinerators are used to deal with the wastes humans produce.
Wastewater:
 Sewage moves to a treatment plant (or septic tank) it is treated and the
is released.
 Effluent:
 Street drains go directly to rivers/lakes therefore any oils,
go
into the
, detergents
.
Wastewater Treatment:
 Wastewater left untreated becomes a breeding ground for harmful bacteria
 The treatment process involves three stages:
, biological and
chemical
1) Physical:
2) Biological:
sewage material is
by the action
of
3) Chemical:
are added to remove
and
Fossil Fuels:
 Coal, oil and natural gas are called
are formed from
 Hydrocarbons are very important in our lives
 Examples of Hydrocarbons:
 Burning fossil fuels is part of the
cycle
because they
.
and part of the C-O
Electrical Energy
 Most of our electricity comes from
generators
Dirty Fuels:
 Fossil fuels can have many other compounds mixed in with them including sulfur,
mercury and
.
 Sour gas is that
has a high
content so the
must be
 Sweet gas has no
Recap:
So What’s the Big Deal?
Your Task:
 Read pages 180-190 and take relevant notes
 Do Check and Reflect page 190
◦ Questions: 1-9, 11
 It is very important that you put some thought into question 11 as this will be the focus
of our next class
Questions:
1. Lightning that occurs during thunder storms is beneficial because it replaces nutrients in
soil. This is part of the
a. Nitrogen cycle
b. Carbon cycle
c. Water cycle
d. Energy cycle
2. Carbon dioxide is put back into air during the process of
a. Transpiration
b. Photosynthesis
c. Respiration
d. Precipitation
3. Draw a simple diagram of the nitrogen cycle.
4. Farmers occasionally plant alfalfa and sweet clover legume crops to build up the nutrients
in their soil. Explain how alfalfa plants build up the nutrients in the soil.
5. A bag of fertilizer has the label 16-20-5
On the chart below, indicate what elements each number represents and say what that
element does- its nutrient value- to ensure a healthy plant
Label Number
16
Element
Nutrient Value
20
5
6. DDT, a pesticide used to control the mosquito population in the mid 1900’s was banned
30 years later. Explain why it is no longer used as an insecticide.
7. What are the steps in sewage treatment? Indicate what happens in each of the three steps
of the process and how the term “effluent” fits into the process.