ESCI 100 Reviewer

Atmosphere

• layer of gas or layer of gases that envelop a planet and is held in place by the gravity of the planetary body

• composed of about 78% nitrogen, 21% oxygen, and 1% of other gases.

Atmospheric Chemistry

study if the chemical process that occur in the Earth’s atmosphere and other planetary atmosphere

Layers of the Earth’s Atmosphere

1. Exosphere 

2. Thermosphere

3. Mesosphere

4. Stratosphere

5. Troposphere

Composition of Air

a mixture of gases which makes up the Earth’s atmosphere

Common Properties of Air

• Colorless and Odorless

• Occupy Space

• Air Exerts Pressure

• Expansion

Colorless and Odorless

has no color and odor, an invisible matter that can only be felt

Occupy Space

mixture of gases, occupies space

Air Exerts Pressure

has weight and pressure exerted by the weight of air known as AIR PRESSURE

Expansion

on heating it expands and occupies more space. The more it expand the thinner it becomes. Hence the pressure of the warm wind is lower than that of cold wind

Chemical Reaction in Atmosphere

process in which various chemical substances in Earth’s atmosphere interact and transform into different compounds

Different Chemical Reaction in Atmosphere

1. Combustion Reaction

2. Ozone Formation

3. Photochemical Smog Formation

4. Acid Rain Formation

5. Aerosol Formation

6. Greenhouse Gas Reaction

7. Nitrogen Oxides (Nox) Formation

8. Volatile Organic Compounds (VOCs) Reaction

9. Hydroxyl Radicals (OH) Reactions

10. Nitrogen Fixation

Combustion Reaction

substance burns in oxygen with the release of carbon dioxide, water and energy in the form of heat, light and even sound.

Ozone Formation

formed in the atmosphere through the series of reactions involving oxygen molecules and sunlight

Photochemical Smog Formation

mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds react to sunlight

Acid Rain Formation

• formed when pollutants, primarily sulfur dioxide, react with atmospheric moisture

• type of rain that contains high level of acidic components, primarily sulfur acid and nitric acid

Aerosol Formation

• “Aerosols” are tiny particles suspended in the atmosphere 

• Aerosols can be formed through various chemical reactions, including the oxidation of sulfur dioxide and nitrogen oxide to form sulfate and nitrate particles

Greenhouse Gas Reaction

“Greenhouse gas” are gases in the Earth’s atmosphere that trap heat

Nitrogen Oxides (Nox) Formation

• Nitrogen oxides (Nox), including nitric oxide (NO) and nitrogen dioxide (NO2), are produced through combustion process.

• These gases are involved in reactions that contribute to the formation of photochemical smog.

• Can also participate in the formation of acid rain.

• Both NO and NO2 are formed during high-temperature combustion in the atmosphere, when oxygen combines with nitrogen.

Volatile Organic Compounds (VOCs) Reaction

• “Volatile organic compounds” are organic compounds that have a high vapor pressure at room temperature.

• High vapor pressure correlates with a low boiling point, which relates to the number of the sample’s molecules in the surrounding air, a trait knows as “valatility”

Hydroxyl Radicals (OH) Reactions

• highly reactivate molecules present in the atmosphere

• removing pollutants from the atmosphere

• non-toxic to humans, animals, and plants

• kills bacteria, virus and mold

4 Types of Hydroxyl Radicals

1. Atmospheric

2. In-vivo

3. Chemical

4. Interstellar

Nitrogen Fixation

• vital process in which atmospheric nitrogen is converted into biologically useful forms, such as ammonia and nitrates

• essential for the availability of nitrogen in ecosystems and the growth of plants

Challenges in Atmospheric and its impact to Agriculture

1. Climate Change

2. Air Pollution

3. Ozone Depletion

4. Acid Rain

5. Stratospheric Jet Stream

6. Space Weather

7. Aerosol Loading

8. Deforestation

Climate Change

refers to long-term shifts in temperatures and weather patterns, mainly caused by human activities especially  burning of fossil fuels

Air Pollution

refers to contamination of the indoor outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere

Ozone Depletion

thinning of the ozone layer present in the upper atmosphere

Acid Rain

includes any form of precipitation with acidic components, such as sulfuric or nitric acid that fall to the ground from the atmosphere in wet or dry forms

Stratospheric Jet Stream

fast, narrow current of air flowing from the west to east that encircles the globe

Space Weather

refers to the variable conditions on the sun and in space

Aerosol Loading

suspensions of solids and/or liquid particles in the air that we breathe

Deforestation

removal of trees can disrupt the carbon cycle, affecting the atmosphere’s ability to absorb and store carbon dioxide.

Water

• an inorganic compound with the chemical formula H20

• transparent, tasteless, odorless, and nearly colorless chemical substance, and it is the main constituent of Earth’s hydrosphere and the fluids of all known living organisms

Bond

• what holds atoms together in molecules

• arise from the electrostatic forces between positively charged atomic nuclei and negatively charged electrons

Atom

smallest unit of matter; composed of three sub-atomic particles: proton, neutron, electron

Electron

• negatively charged subatomic particle that can be either bound to an atom or free

• together protons and electrons form an atom’s nucleus

Proton

• subatomic particle with a positive electrical charge

• found in every atomic nucleus of every element 

Nuetron

have neutral electric charge and slightly more mass than positively charged protons

Molecule

group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Covalent Bond

sharing of electrons to form electron pairs between atoms

Hydrogen Bonding

Water Bond - consist of 1 atom of oxygen and 2 atoms of hydrogen

Properties of Water

• Adhesion Force

• Cohesion Force

Adhesion

• joining two dissimilar substances is known as adhesion

• force necessary for a liquid droplet to separate from a surface it comes into contact with is known as the adhesion force

Cohesion Force

• defined as the force of attraction between two similar substances or molecules

• The condition known as cohesive force describes how similar molecules are drawn to one another and stick to one another

Cohesion Force: Surface Tension

• tendency to contract into the smallest possible surface area

• Water has a very high surface tension because water is a polar molecule, its molecules are more attracted to one another than other molecules

Cohesion Force: Tensile Strength

• maximum force per unit area that a continuous column of water can bear before breaking

Specific Heat Capacity

quantity of thermal energy required to increase a substance’s temperature by one degree Celsius per gram

Heat of Vaporization

amount of heat needed to change the state of a substance from a liquid to vapor. It is also known as the enthalpy of vaporization, with the amount of 4.07 × 10⁴ J/mol

Heat of Fusion

the energy required to change a substance from the solid state to the liquid state. Also known as, the enthalpy of heat of fusion, with the value of 6009.5 J/mol

Water Quality

Refers to the chemical, physical, and biological characteristics of water based on the standards of its usage

Dissolve Oxygen

also known as DO, is an oxygen dissolve in water

Two Types of Mixture

• Solution

• Suspension

Solution

homogeneous mixture composed of two or more substances

Solute

substance that is being dissolved

Solvent

dissolves the solute

Suspension

heterogeneous mixture in which the solid particles are spread throughout the liquid without dissolving in it

Two Ways of Oxygen Enters in Water

• Atmosphere

• Photosynthesis

What happen in the dissolved oxygen

• It essential for the survival of fish and other aquatic organisms.

• Oxygen dissolves in surface water due to the aerating action of winds.

• Oxygen is also introduced into the water as a byproduct of aquatic plant photosynthesis

Electrical Conductivity

• measure of the capability of the material to pass the flow of electric current

• denoted by the Greek letter ρ

• inverse of the resistivity and is given by σ = 1/ρ

pH Level

• measures how acidic or basic a solution is

• Formula: pH = - log [H3O+].

Alkalinity

• the capability of water to neutralize acids This ability is referred to as a buffering capacity

• measures how much acid can be added to a water body before a large pH change occurs

Hardness

measurement of the concentration of total divalent ions present in water

2 Types of Water Hardness

1. Temporary Hardness

2. Permanent Hardness

Temporary Hardness

• occurs due to the presence of calcium hydrogencarbonate and magnesium hydrogencarbonate

• can be removed by boiling water

Permanent Hardness

• occurs due to the presence of calcium sulfate

• cannot be removed by boiling water

Soil Chemistry

branch of soil science the deals with the chemical composition, chemical reactions and chemical properties in soils

Soil

dynamic living system in which ions and molecules constantly may move from one phase to the other, while ions and molecules constantly may move from one phase to the other, while interacting with each other

Soil chemical properties

based on the concentrations, and/or proportions of dissolved species in soil water and/or on the ion exchange complex

Soil Components

• Inorganic Components

• Organic Components

Inorganic Components

• refer to the non-living materials present in the soil

• primarily derived from the weathering and breakdown of rocks and minerals over time

Main Inorganic Components found in Soil

• Mineral Particles

• Rocks and minerals

• Water and air

Mineral particles

primary inorganic components of soil, classified based on their size intro three categories: sand, silt, and clay

Rock and minerals

Soil contains various types of rocks and minerals, which contribute to its mineral composition

Water and air

While not strictly inorganic, water and air are crucial components of soil

Organic

refer to the living and decaying organisms, as well as their byproducts, that contribute to the fertility and structure of soil

Key Organic Components found in Soil

• Humus

• Plant Residue

• Animal Residue

• Micoorganisms

Humus

dark decomposed organic matter in soil

Plant Residue

Plant materials such as leaves, stems, roots, and fallen branches contribute to the organic component of soil

Animal Residue

Animal waste, carcasses, and other organic materials from animals also contribute to soil organic matter

Microorganisms

play a vital role in decomposing organic matter, cycling nutrients, and enhancing soil fertility

Soil Structure

refers to the aggregation of individual soil particles into compound groups orclusters of particles

Granular Structure

desirable soil structure characterized by the presence of small, rounded aggregates

Blocky Structure

consists of irregular, block-like aggregates

Prismatic structure

consists of vertical, column-like aggregates

Single-grained Structure

occurs when soil particles are not bound together and exist as separate particles

Massive Structure

refers to soil structure where soil particles are tightly packed together without any visible aggregation or distinct arrangement

Plate-like Structure

soil particles are arranged in thin, flat plates or sheets

Crumb structure

desirable type of soil structure characterized by the presence of small, loose and crumb-like aggregates

Plant Nutrients from Soil

Soil is a major source of nutrients needed by plants for growth. The three main nutrients are nitrogen (N), phosphorus (P) and potassium (K). Together they make up the trio known as NPK. Other important nutrients are calcium, magnesium and sulfur.

Two Main Categories of Nutrients

• Macronutrients

• Micronutrients

Macronutirents

• required by plants in larger quantities

• Soil pH significantly impacts the availability of macronutrients such as nitrogen (N), phosphorus (P), and potassium (K)

Nitrogen (N): In acidic soils, the availability of nitrogen increases, while alkaline soils can reduce nitrogen availability.

Phosphorus (P): Phosphorus availability decreases in alkaline soils due to the formation of insoluble compounds with calcium and iron

Potassium (K): Soil pH has a minimal effect on potassium availability. However, extremely acidic or alkaline conditions can reduce potassium uptake by plants

Micronutrients

• needed in smaller amounts

• Soil pH strongly influences the availability of micronutrients such as iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), and boron (B)

Iron (Fe) and Manganese (Mn): Acidic soils promote the solubility and availability of iron and manganese, while alkaline conditions can lead to their precipitation, reducing their availability to plants

Zinc (Zn), Copper (Cu), and Boron (B): These micronutrients are more available in acidic soils. Alkaline conditions can cause their fixation or precipitation, rendering them less accessible to plants

Soil pH

• refers to the measure of acidity or alkalinity of soil. It is a vital property of soil that affects the availability and uptake of essential nutrients by plants

• determined by the concentration of hydrogen ions (H+) in the soil solution

• plays a crucial role in the availability and uptake of nutrients by plants. It affects the chemical reactions and transformations that occur in the soil, which in turn influence nutrient availability

pH and Toxicity

• pH measure of the acidity or alkalinity of a solution, ranging from 0 to 14.

• A pH value of 7 is considered neutral, while values below 7 indicate acidity and values above 7 indicate alkalinity.

• pH plays a crucial role in determining the toxicity of certain substances

• Toxicity refers to the degree to which a substance can harm living organisms.

• The pH of the environment can significantly influence the toxicity of certain substances

pH and Cation Exchange Capacity (CEC)

• pH and cation exchange capacity (CEC) are both important concepts in soil science and agriculture

• pH plays a crucial role in determining nutrient availability and microbial activity. Different plants have different pH requirements for optimal growth

• CEC is a measure of a soil's ability to retain and exchange positively charged ions, known as cations. It is an important indicator of soil fertility and nutrient-holding capacity

Cation Exchange Capacity (CEC)

is a useful indicator of soil fertility because it shows the soil’s ability to supply three important plant nutrients: calcium, magnesium, and potassium

ph and Soil Organism

• plays a significant role in determining the types and activities of soil organisms. Soil organisms, including bacteria, fungi, protozoa, nematodes, earthworms, and many others, are crucial for maintaining soil health and fertility

• pH range 5.5–6.5 is optimal for plant growth as the availability of nutrients is optimal

Soil Acidity 

Acidity in soil is primarily caused by the presence of hydrogen ions (H+). When certain minerals in the soil break down or when organic matter decomposes, they release hydrogen ions, which can increase soil acidity

Properties of Air

1. Air has mass

2. Air occupies space, or has volume

3. Air has density

4. Air exerts pressure

Chemistry of Water

• Density is an important property of water because small changes in density result in a significant change in water pressure at great depths

• Polarity means a molecule or bond has a separation of electric charge, creating a slightly positive end and a slightly negative end due to unequal sharing of electrons, determined by differences in electronegativity.

• Cohesive Property means its molecules stick to each other due to strong hydrogen bonds, creating high surface tension (like water beading up or a needle floating) and enabling capillary action (water moving up xylem in plants), essential for life.