unit c: environmental chemistry · pdf filechemicals in the environment science 9 unit c...

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Science 9

Science 9 Unit C Section 1.0 1

The environment is made up of chemicals that can support or harm living things.


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Topic 1.1 Chemicals in the Environment


Reference Book pg. 2

Chemicals, chemicals everywhere! All living things are made of chemicals and depend on

chemicals to survive.

Without carbon dioxide and water, green plants could not produce sugar for food (through photosynthesis):

6 CO2 + 6 H2O → 6 O2 + C6H12O6

Photosynthesis is a process used by plants and other organisms to convert light energy from the sun into chemical energy that can be used to fuel an organism’s activities.


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Chemicals, chemicals everywhere! All living things are made of chemicals and depend on

chemicals to survive. Without oxygen, plants and animals could not carry out

cellular respiration:

6O2 + C6H12O6 → 6 CO2 + 6 H2O

Cellular respiration is when cells take in food and break up sugars into a form that the cell can use as energy. It takes place in all organisms.

Science 9 Unit C Section 1.0 5Page 2

Recall: ELEMENTS Recall that elements are

pure substances that cannot be broken down into other substances.

Some elements form chemical compounds that are used and reused by living things.

The repeating changes of these elements and water as they move through ecosystems is called a cycle.

The element nitrogen also cycles in this way.


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Nitrogen Nitrogen is important for living things. For example,

plants require nitrogen to make substances necessary for life.

Air is about 78% nitrogen in the form of nitrogen gas (N2(g)).

However, plants can use nitrogen only when it is combined with other elements, such as hydrogen and oxygen.


Nitrogen Fixation But plants can’t use this “free” nitrogen directly. It has to be

“fixed” in compounds with other elements.

Nitrogen fixation is the process of changing free nitrogen so that the nitrogen atoms can combine with other elements to form compounds that organisms can use.

Science 9 Unit C Section 1.0 8#1

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Nitrogen Fixation Certain types of bacteria do

most of the nitrogen fixation in the soil. Some of these bacteria are located in the root nodules of specific types of plants. The bacteria in these nodules

are able to separate the nitrogen atoms so they can form compounds with other elements, such as hydrogen and oxygen.

Lightning also converts nitrogen in the air to nitrogen compounds that plants can use.


The Nitrogen Cycle


#2

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http://www.classzone.com/books/ml_science_share/vis_sim/em05_pg20_nitrogen/em05_pg20_nitrogen.html


Pollution Pollution is any change in the environment that

produces a condition that is harmful to living things.

For example:

Smog caused by vehicle exhaust emissions is pollution because it makes it hard for people and other animals to breathe.

Forest fires produce similar chemical pollution.

Oil and chemical spills from boats, oil tankers, or power plants also pollute the environment.


http://www.classzone.com/books/ml_science_share/vis_sim/em05_pg20_nitrogen/em05_pg20_nitrogen.html

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Human Activities & Points of View Various human activities, such as the use of chemicals,

can become an issue.

An issue is any subject of importance about which people have strong, conflicting points of view.


Recall: Viewpointsi. Cultural ii. Ecological

interest in the customs and practices of a particular group of people

interest in the protection of the natural environment


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Recall: Viewpointsiii. Economic iv. Educational

interest in the financial aspects of the situation

interest in acquiring and sharing knowledge and skills


Recall: Viewpointsv. Esthetic vi. Ethical

interest in the beauty in art and nature

interest in beliefs about what is right and wrong


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Recall: Viewpointsvii. Health & Safety viii. Historical

interest in physical and mental well-being

interest in knowledge dealing with past events


Recall: Viewpointsix. Political x. Recreational

interest in the effect of the issue on governments, politicians, and political parties

interest in leisure activities


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Recall: Viewpointsxi. Scientific xii. Social

interest in knowledge based on the inquiry process of Science

interest in human relationships, public welfare, or society


Recall: Viewpointsxiii. Technological

interest in the design and use of tools and processes that solve practical problems to satisfy peoples’ wants and needs


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Can you identify the viewpoints presented in the video below?“Keystone Pipeline – No Brainer” (3:41)


Can you identify the viewpoints presented in the video below?“The Keystone Pipeline…Explained” (1:47)


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Agricultural Activities Farmers must have an understanding of chemistry to

produce good crops.

They have to know what chemicals to add to soil to improve plant growth and what chemicals to treat plants with to protect them from pests.


Fertilizers A fertilizer is a substance

that enriches soil so that plants will grow better.

Fertilizers are described by the major nutrient elements they contain.

These elements are nitrogen, phosphorus, and potassium.

Science 9 Unit C Section 1.0 24#6, #7

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Fertilizer Labels The three numbers 24-6-12

on the label indicate that this fertilizer contains 24%nitrogen compounds, 6%phosphorus compounds, and 12% potassium compounds.

Some fertilizers have a fourth number and the letter “S” on the label to indicate that they contain sulfur as a major ingredient.


Too much of anything… Too much fertilizer may

damage the crop it’s supposed to help. If fertilizer enters ponds, streams, lakes, or rivers, it may damage water ecosystems by changing the concentration of chemicals.


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Pesticides Pesticides are chemicals used to kill pests.

A pest is an organism that harms:

people, such as bed bugs, head lice, mosquitos, etc.

crops, such as grasshoppers, aphids, beetles, worms, etc.

structures, like cockroaches, termites, moths, etc.


Types of Pesticides Pesticides are grouped according to the pest they kill:

Herbicides kill or control weeds.

Insecticides kill or control insects.

Fungicides kill fungi.


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Other Problems with Pesticides? Improper application of pesticides can be harmful to

people and other non-pest organisms.

Some pesticides are not selective—they kill both pest and non-pest species (i.e. armyworm vs. bees).

Another problem occurs with pesticides that stay in the environment for a long time (i.e. DDT).

Some pests become resistant to pesticides, so new pesticides must be developed to control them.


Pesticide Blamed in 8 Month Old’s Death in Fort McMurray, February 23, 2015 (2:15)


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http://youtu.be/y4OUOgi9aAk


Solid Wastes Chemicals may be introduced into the environment

when we dispose of solid waste or wastewater from households, industrial plants, commercial buildings, institutions, and construction and demolition sites. It includes large items, such as machinery, all the way down to small items, such as the caps on plastic drink bottles.


http://youtu.be/y4OUOgi9aAk

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Solid Wastes Some solid waste can be reused or recycled, but most

of it is placed in landfill sites. Some hazardous wastes are burned in special plants called incinerators, which burn at very high temperatures. Emissions from incinerators may contribute to air pollution.


Sanitary Landfill Sites Sanitary landfill sites are

specially built to prevent waste chemicals from moving into the soil.

Sanitary landfills use plastic liners and compacted clay to prevent corroded chemicals from entering the soil and the groundwater.


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http://youtu.be/lsyg472MQp8


Wastewater

Wastewater from your kitchen,

bathroom, and laundry

is called sewage.

Sewage moves

through pipes into a septic tank or to a

sewage treatment

plant.

A septic tank is an underground container where bacteria break

down the organic materials before they are moved

out to the soil. A sewage

treatment plant treats wastes so

they can be disposed of

safely.

Treated wastewater or

effluent is released into

rivers or lakes. It may contain nitrogen and phosphorus

from the breakdown of sewage during

treatment.

Runoff water from street

drains may go directly into a

river/lake through large pipes called

storm sewers, and contain chemicals

washed off the street, such as oil

and salt.


http://youtu.be/lsyg472MQp8

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http://youtu.be/NpkNOB0EJ2M

http://youtu.be/9QZgX0j3Wdw


http://youtu.be/jakJ-Tf79ac

http://youtu.be/_8VqWKZIPrM


http://youtu.be/NpkNOB0EJ2M

http://youtu.be/9QZgX0j3Wdw

http://youtu.be/jakJ-Tf79ac

http://youtu.be/_8VqWKZIPrM

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Fossil Fuels Coal, oil, and natural gas are called fossil fuels

because they are fuels formed from dead plants and animals.

They are called hydrocarbons because they are mainly made up of the elements hydrogen and carbon.

They may also contain oxygen, nitrogen, and sulfur. Fossil fuels may contain traces of other elements such as mercury and lead.


Fuel Combustion The combustion of fossil fuels may also release

pollutants such as sulfur dioxide, nitrogen oxides, and traces of mercury and lead into the air.


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Burning Fossil Fuels When fossil fuels are burned in homes, vehicles, and

industrial plants, they produce large amounts of carbon dioxide and water vapour.

The general reaction equation for this combustion reaction is:

hydrocarbon + oxygen → carbon dioxide + water + energy


Fuel Combustion The combustion of fossil fuels may also release

pollutants such as sulfur dioxide, nitrogen oxides, and traces of mercury and lead into the air.

Also, consider the products of the combustion of methane (in natural gas):

CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) + energy

And the products of the combustion of propane (used in barbeques, vehicles, and some home appliances):

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) + energy


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Natural Gas Processing Natural gas is also processed to eliminate unwanted

substances such as hydrogen sulfide, a poisonous chemical.

Natural gas that contains hydrogen sulfide is called “sour” gas.

If no hydrogen sulfide is present, the gas is considered “sweet.”


Industrial Processes Industrial processes such as electrical power

generation, mineral processing, and fertilizer production may release chemicals into the air. A common industrial process in Alberta is natural gas processing.

Natural gas is processed for different uses by separating its components such as methane, ethane, propane, butane, nitrogen gas, carbon dioxide, hydrogen sulfide, helium, and traces of metals such as mercury.


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Homework! Reference Book

Page 7 (Test Your Understanding)

# 21 – 25

Read Textbook

Page 191 – 195

Reference Book

Page 7 – 9 (Topic 1.2)

# 1 – 9

Science 8 Unit B Section 1.0 45

Topic 1.2 Acids and Bases



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http://youtu.be/3U9n4BV2618


pH Acidity is measured according to the pH scale.

Most solutions have a pH in a range of 0 to 14. The pHnumber of a solution indicates its acidity. It measures the concentration of hydrogen ions in a solution.


http://youtu.be/3U9n4BV2618

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What is an acid? An acid is a compound that dissolves in water to form

a solution with a pH lower than 7.

The pH number of a solution indicates its acidity. It measures the concentration of H+ ions in a solution.

Example: Lemon juice, tomatoes, vinegar, stomach acid


What is a base? A base is a compound that dissolves in water to form a

solution with a pH higher than 7.

Example: Shampoo, Baking Soda, Bleach, Toothpaste, Drain Cleaner, Ammonia


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What is a neutral solution? A neutral substance is

neither an acid nor a base.

It has a pH of 7.


pH Scale The difference between one number and the next on

the pH scale represents a 10-fold difference.

For example, a solution with a pH of 3 is 10 times more acidic than a solution with a pH of 4.

Similarly a solution with a pH of 9 is 10 times more basic than a solution with a pH of 8.


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pH Scale


Acidic Basic

#4

http://player.discoveryeducation.ca/index.cfm?guidAssetId=446195A4-E360-4FB5-9551-17DFDAE04BCE



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Measuring pH: litmus paper Acid-base indicators are

substances that can change colour when they are placed in solutions.

Red litmus paper turns blue in a base but remains red in an acid.

Blue litmus paper turns red in an acid but remains blue in a base.


Measuring pH: universal indicators A universal indicator is a

mixture of indicators that change colour over a wide pH range. The pH of a clear fluid can

be identified by the colour of the fluid after several drops of the indicator have been added.

You need to use a colour chart to compare the colour of the test fluid with that of a known standard.


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Example: Universal IndicatorsBromothymol blue Methyl orange


Measuring pH: pH meters You can use a pH meter

or acid-base indicators to measure pH.

A pH meter consists of a probe attached to a meter. To test a fluid, you submerge the tip of the probe in it, and the meter indicates the fluid’s pH.


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Neutralization If you have an upset

stomach, you might take an antacid to help you feel better. An antacid is a mild base that reacts with the acid in your stomach to neutralize it. This acid-base reaction is called neutralization.


Neutralization Reaction A neutralization reaction is a reaction between an

acid and a base that produces water and a compound called a salt. Here is the equation for that neutralization reaction:

HCl(aq) + NaOH(aq) → NaCl(s) + H2O(l)

acid + base → salt + water


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Acid Rain


Neutralizing Acid Rain Normal rain has a pH of about 5.6.

Acid rain has a pH of 5.5 and below. Acidic lakes are sometimes treated

with lime (calcium hydroxide) to neutralize them. The lime is mixed with water so that

it dissolves. A chemical reaction takes place

between this limewater and the dilute sulfuric acid of the lake’s water.

The reaction produces calcium sulfate (a salt) and water.

If all the acid and all the base are used up, the solution becomes neutral.


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Treating acidic lakes with calcium hydroxide The equation for the reaction is:

Ca(OH)2(aq) + H2SO4(aq) → CaSO4(s) + 2 H2O(l)

calcium hydroxide + sulfuric acid → calcium sulfate + water




# 10 – 12

Read Textbook

Page 196 – 203

Reference Book

Page 10 – 11 (Topic 1.3)

# 1 – 9


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Topic 1.3 Common Substances Essential to Living Things



Essential Elements Our bodies need about 25 elements for normal growth.

Carbon (C), hydrogen (H), and oxygen (O) are the most common chemical elements in living organisms.


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Organic Compounds Complex compounds

whose molecules contain carbon are organic compounds.

Example: fossil fuels -petroleum, coal, and natural gas, such as methane (CH4), ethanol (CH3CH2OH), acetone (CH3COCH3)

**Exceptions**: The following are inorganic compounds:

carbon dioxide (CO2)

carbon monoxide (CO)

carbonates (CO32-)

cyanides (CN-)


Inorganic Compounds Inorganic compounds are compounds whose

molecules do not contain carbon.

Example: sodium chloride (NaCl), water (H2O), hydrochloric acid (HCl), ozone (O3), baking soda

Also included as inorganic compounds are carbon dioxide, carbon monoxide, carbonates, and cyanides.


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Organic or Inorganic?Items

Organic/ Inorganic

Explanation

oxygen inorganic O2 (does not contain carbon)

distilled water inorganic H2O (does not contain carbon)

sugar organic i.e. glucose: C6H12O6 (contains carbon)

motor oil organic Blend of oils that contain carbon and hydrogen

hydrochloric acid inorganic HCl (does not contain carbon)

rust inorganic iron oxides i.e. Fe(OH)3 (does not contain carbon)

vitamin C organic C6H8O6 (contains carbon)

glass inorganic SiO2 (does not contain carbon)

fat organic (contain carbon)

rubber organic (contain carbon)


#4

What are nutrients? Nutrients are elements and compounds that

organisms need for living, growing, and reproducing.

Elements that are needed in relatively large amounts are called macronutrients (“macro-” means large or large scale).

Example: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, magnesium, calcium, and sulfur


http://en.wikipedia.org/wiki/Carbon

http://en.wikipedia.org/wiki/Hydrogen

http://en.wikipedia.org/wiki/Oxygen

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What are nutrients? Nutrients are elements and compounds that

organisms need for living, growing, and reproducing.

Elements that are needed in relatively small amounts are called micronutrients (“micro-” means very smallor small scale).

Example: niacin, iron, selenium, sodium, fluoride, iodine, copper, zinc, and vitamins A, B, C, D, E, and K


Optimum Amounts The optimum amount of a substance is the amount

that provides an organism with the best health.

Example: Selenium, along with vitamin E, helps to protect cell membranes from damage caused by hydrogen peroxide, a poison that is produced in some chemical reactions in cells.

For humans, at least 0.000 070 g (70 micrograms) of selenium per day is recommended.

Selenium deficiency is associated with diseases

of the heart, bones, and joints.


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Too much of anything… The maximum intake level

of selenium is 0.000 400 g (400 micrograms) per day.

Selenium poisoning, known as selenosis, includes symptoms such as a garlic odor on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability, and neurological damage. Extreme cases of selenosis can result in liver and lung damage, and death.


Food Sources of Selenium Brazilian nuts are perhaps the richest dietary

source of selenium, with a serving of 6 nuts supplying 774% of the daily recommended intake!

Sunflower Seeds

Fish (Tuna, Halibut, Sardines)

Shellfish (Oysters, Shrimp, Scallops)

Poultry (Chicken, Turkey)

Eggs


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Human & Plant Composition


Page 197

#8

Types of Organic Molecules Most chemicals in humans and other living things are

organic compounds.

Four important classes of organic compounds are:

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic acids


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Carbohydrates Carbohydrates are

organic molecules made up of atoms of carbon, hydrogen, and oxygen.

When we eat food such as pasta, rice, potatoes, fruits, and bread, we are eating carbohydrates.

These atoms can form simple molecules, such as sugar, or large, complex molecules, such as starch, and cellulose.


Lipids Fats, oils, and waxes are

lipids—compounds composed of many carbon, hydrogen, and oxygenatoms.

Our skin produces oils, and our bodies store food in the form of fat.

Plant products such as canola seeds, corn, peanuts, soybeans, walnuts, and cashewscontain large amounts of oils.


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Proteins and Amino Acids Foods such as meat, fish, eggs, and

dairy products add proteins to our diet.

Proteins are used by organisms for growth and repair, and as a source of energy. They are the main component of enzymes (catalysts that control chemical reactions in organisms).

A protein is an organic compound made up of units called amino acids (carbon, hydrogen, oxygen, nitrogen, and/or sulfur). In general, a protein contains

between 40 and 500 amino acid units.


Nucleic Acids Nucleic acids are the largest

and most complicated molecules found in living things.

All cells contain two important nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

DNA and RNA are made up of three substances: phosphates, asimple sugar called ribose, and nitrogen-containing molecules.

Nucleic acids play a major role in heredity and in controlling a cell’s activities.


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#10 – 11

Read Textbook

Page 204 – 209

Reference Book

Page 11 – 13 (Topic 1.4)

# 1 – 9


Topic 1.4 How Organisms Take in Substances



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Interdependence Plants and animals rely on the environment for the

substances they need to live. Plants take in inorganiccompounds to make organic compounds.

Consumers must rely on organic compounds made by plants for their energy, growth, and repair. Consumers obtain these compounds by either eating plants or eating other organisms that eat plants.


Taking in Chemicals When organisms take in the chemicals they need, they

may also be taking in other substances. Sometimes, these are harmless. For example, when you drink pop, you are taking in

water, which you need, but you are also taking in the flavouring and colouring in the pop.

Sometimes the other substances may be harmful. For example, a lake beside a coal-fired generating plant may contain high levels of mercury. If you ate fish caught near the plant, you would take in this harmful substance.


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http://youtu.be/qotIWgL7zFs


Uptake of Substances by Plants: Diffusion Some nutrients move into

the roots of plants from an area of higher concentration outside the roots to the area of lower concentration within the roots. This passive uptake, known as diffusion, does not require the plant to use any energy.

The movement continues until the concentration of nutrients is the same both inside and outside the plant roots.



http://youtu.be/qotIWgL7zFs

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Uptake of Substances by Plants: Osmosis Water moves into plant roots by

a special type of diffusion called osmosis.

In the process of osmosis, watermoves through the plant’s roots from an area where there are more water molecules to an area where there are fewer water molecules.

As the plant uses water for its growth and maintenance, it draws water up from the roots. As the number of water molecules within the roots decreases, more water molecules move into the roots from the surrounding soil.


Uptake of Substances by Plants: Active Transport Plants need high concentrations

of some nutrients in their roots. To maintain these high

concentrations, plants must use energy to move some nutrients from the soil, an area of lowerconcentration, into their roots, an area of higher concentration.

To move nutrients in this direction, plants use a process called active transport.

In active transport, plants must use energy to move the molecules of nutrients in the direction opposite to diffusion.


Direction of Movement of Particles in Active Transport

#3, #4

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Ingestion Humans and other animals obtain the 25 elements our

bodies need for normal growth and function from the air we breathe and the food we eat.

The process of taking food into our bodies is called ingestion. Every time you drink or eat, you are ingesting food. Most of the ingested food must be broken down into smaller particles so our bodies can absorb the nutrients from it.


Recall: Two Types of Digestion1. Mechanical digestion involves the physical

breakdown of food into very small pieces (i.e. chewing).

2. Chemical digestion involves the breakdown of large particles into smaller particles by substances called enzymes.

Science 8 Unit B Section 3.0 90#6

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Hydrolysis Chemical breakdown occurs in the

mouth, stomach, and small intestine with the help of enzymes that speed up the chemical reactions.

The breakdown or digestion of large organic molecules occurs by a process called hydrolysis.

“Hydro” refers to water and “lysis” means breakdown.


Hydrolysis A substance that is broken down by hydrolysis has

been hydrolyzed.

For example, when you eat potatoes, the large starch molecules are hydrolyzed into double sugars called maltose, and then into single sugars called glucose.

This reaction can be written in the following way:

C12H22O11(aq) + H2O(l)→ 2 C6H12O6(aq)

maltose + water → glucose


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Other Environments Where organisms live affects how and when they can

obtain nutrients.

For example, plants living in the north can obtain nutrients only during a short growing season. Plants in the desert often have methods to limit the growth of other plants around them.

Example: Red snow algae manage to survive on a substrate that is near freezing, poor in nutrients, and often acidic. The red pigment masks the green chloroplasts that enable the algae to carry out photosynthesis.


Substrates A substrate is the

material on which an organism moves or lives.

Some organisms are attached to their substrate.

Example: Anemones are animals that live attached to rocks in the ocean. They capture food with their tentacles.


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Science 9 Unit C Section 1.0 95Text Page 208



# 10 – 12

Extra Review

Textbook Assess Your Learning, Page

211

# 1 – 9

Section 1 Review Handout


unit c: environmental chemistry · pdf filechemicals in the environment science 9 unit c...

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