Water has unusual properties due to its polarity and ability to form hydrogen bonds between molecules. It has a high heat capacity which moderates temperatures on Earth. Water's density peaks at 4°C, allowing lakes and oceans to retain heat in winter and resist rapid changes in season. Hydrogen bonding enables water to act as a solvent for life's biochemical reactions and transport systems. The pH scale measures hydrogen ion concentration in aqueous solutions, which is tightly regulated in living systems.
It reasonably can be argued that that most participants in the roofing, building and design trades tend to either take water for granted or lack the basic understanding of both the chemistry and physics that play such a large role in water accumulation within a building enclosure. Sure, people in the construction business fear the effects of excess water, but few have taken the time to understand why it acts the way it does.
The driving forces that cause moisture movement are fundamental properties of nature; therefore, preventing water infiltration and resulting damage at the typical building project requires close attention during the design and construction processes to all potential moisture sources and routes.
Seven fundamental aspects of water are presented in Water 101 to provide Trinity | ERD forensic personnel and our clients an essential knowledge base for the physical properties of water.
Most foods will not support the growth of bacteria if their water activity is less than 0.85, because at this water activity there is not enough water available for the bacteria to grow.
However, yeasts can grow at water activities as low as 0.70, while some molds will grow even at water activities as low as 0.60!
Foods with water activities in this range usually have preservatives added to prevent the growth of yeasts and molds.
Acidic foods with a pH less than 4.6, such as tomato sauce, retard the growth of microorganisms. Thus an acidic food with a water activity less than 0.85 is relatively shelf stable, especially if it is stored in the refrigerator.
In this case, low pH, water activity and temperature combine to provide good insurance against the growth of harmful pathogens.
It reasonably can be argued that that most participants in the roofing, building and design trades tend to either take water for granted or lack the basic understanding of both the chemistry and physics that play such a large role in water accumulation within a building enclosure. Sure, people in the construction business fear the effects of excess water, but few have taken the time to understand why it acts the way it does.
The driving forces that cause moisture movement are fundamental properties of nature; therefore, preventing water infiltration and resulting damage at the typical building project requires close attention during the design and construction processes to all potential moisture sources and routes.
Seven fundamental aspects of water are presented in Water 101 to provide Trinity | ERD forensic personnel and our clients an essential knowledge base for the physical properties of water.
Most foods will not support the growth of bacteria if their water activity is less than 0.85, because at this water activity there is not enough water available for the bacteria to grow.
However, yeasts can grow at water activities as low as 0.70, while some molds will grow even at water activities as low as 0.60!
Foods with water activities in this range usually have preservatives added to prevent the growth of yeasts and molds.
Acidic foods with a pH less than 4.6, such as tomato sauce, retard the growth of microorganisms. Thus an acidic food with a water activity less than 0.85 is relatively shelf stable, especially if it is stored in the refrigerator.
In this case, low pH, water activity and temperature combine to provide good insurance against the growth of harmful pathogens.
Classification of marine environment pptAshish sahu
The main divisions of the marine environment. The two primary divisions of the sea are the benthic and the pelagic. The former includes all of the ocean floor, while the latter includes the whole mass of water. ... The deep-sea system is divided into an upper (archibenthic) and a lower (abyssal-benthic) zone.
Water activity is the moisture content of the food which is available for microbial growth.By controlling water activity the food can be preserved for longer duration
Classification of marine environment pptAshish sahu
The main divisions of the marine environment. The two primary divisions of the sea are the benthic and the pelagic. The former includes all of the ocean floor, while the latter includes the whole mass of water. ... The deep-sea system is divided into an upper (archibenthic) and a lower (abyssal-benthic) zone.
Water activity is the moisture content of the food which is available for microbial growth.By controlling water activity the food can be preserved for longer duration
Properties of water and aqueous solutionssabir shah
Akhuwat Faisalabad Institute Of Research Science and
Technology.....
This video is a course context of 1st prof Bs (hons) biotechnology.. which is prepared by momin khan niazi...........
a presentation of how life originated on earth due to chemicals and how these chemicals represent the building blocks of life all around us.
by Dr. tithi parija (asst. professor) from KIIT school of biotechnology
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
2. Properties of Water
• Polar molecule
• Cohesion and
adhesion
• High specific heat
• Density – greatest
at 4oC
• Universal solvent
of life
3. Polarity of Water
• In a water molecule two hydrogen atoms form
single polar covalent bonds with an oxygen
atom. Gives water more structure than other
liquids
– Because oxygen is more electronegative, the region
around oxygen has a partial negative charge.
– The region near the two hydrogen atoms has a
partial positive charge.
• A water molecule is a polar molecule with
opposite ends of the molecule with opposite
charges.
5. HYDROGEN BONDS
• Hold water molecules
together
• Each water molecule can
form a maximum of 4
hydrogen bonds
• The hydrogen bonds
joining water molecules
are weak, about 1/20th as
strong as covalent bonds.
• They form, break, and
reform with great
frequency
• Extraordinary Properties
that are a result of hydrogen
bonds.
– Cohesive behavior
– Resists changes in
temperature
– High heat of vaporization
– Expands when it freezes
– Versatile solvent
6. Organisms Depend on Cohesion
• Cohesion is responsible for the
transport of the water column in
plants
• Cohesion among water molecules
plays a key role in the transport of
water against gravity in plants
• Adhesion, clinging
of one substance to
another, contributes
too, as water adheres
to the wall of the
vessels.
Hydrogen bonds hold the substance
together, a phenomenon called cohesion
8. Moderates Temperatures on Earth
• What is kinetic energy?
• Heat?
• Temperature?
• Calorie?
• What is the difference
in cal and Cal(kcal)?
• What is specific heat?
Celsius Scale at Sea Level
100oC Water boils
37oC Human body
temperature
23oC Room temperature
0oC Water freezes
Water stabilizes air temperatures by absorbing heat from
warmer air and releasing heat to cooler air.
Water can absorb or release relatively large amounts of heat
with only a slight change in its own temperature.
9. Three-fourths of the earth is covered
by water. The water serves as a
large heat sink responsible for:
1. Prevention of temperature
fluctuations that are outside the
range suitable for life.
2. Coastal areas having a mild
climate
3. A stable marine environment
Specific Heat is the amount of heat that must be
absorbed or lost for one gram of a substance to
change its temperature by 1oC.
10. Evaporative Cooling
• The cooling of a
surface occurs when
the liquid evaporates
• This is responsible for:
– Moderating earth’s
climate
– Stabilizes
temperature in
aquatic ecosystems
– Preventing organisms
from overheating
11. Density of Water
• Most dense at 4oC
• Contracts until 4oC
• Expands from 4oC to
0oC
The density of water:
1. Prevents water from freezing from the bottom up.
2. Ice forms on the surface first—the freezing of the
water releases heat to the water below creating
insulation.
3. Makes transition between season less abrupt.
13. Solvent for Life
• Solution
– Solute
– solvent
• Aqueous solution
• Hydrophilic
– Ionic compounds
dissolve in water
– Polar molecules
(generally) are water
soluble
• Hydrophobic
– Nonpolar compounds
14. Most biochemical reactions
involve solutes dissolved in water.
• There are two important
quantitative proprieties of aqueous
solutions.
–1. Concentration
–2. pH
15. Concentration of a Solution
• Molecular weight – sum of the weights of all atoms in
a molecule (daltons)
• Mole – amount of a substance that has a mass in
grams numerically equivalent to its molecular weight
in daltons.
• Avogadro’s number – 6.02 X 1023
– A mole of one substance has the same number of molecules
as a mole of any other substance.
17. • A simpler way to view this process is that a
water molecule dissociates into a hydrogen
ion and a hydroxide ion:
– H2O <=> H+ + OH-
• This reaction is reversible.
• At equilibrium the concentration of water
molecules greatly exceeds that of H+ and
OH-.
• In pure water only one water molecule in
every 554 million is dissociated.
– At equilibrium, the concentration of H+
or OH- is 10-7M (25°C) .
18. Acids and Bases
• An acid is a substance that
increases the hydrogen ion
concentration in a solution.
• Any substance that reduces the
hydrogen ion concentration in a
solution is a base.
– Some bases reduce H+ directly by
accepting hydrogen ions.
• Strong acids and bases complete
dissociate in water.
• Weak acids and bases dissociate
only partially and reversibly.
19. pH Scale
• The pH scale in any aqueous solution :
– [ H+ ] [OH-] = 10-14
• Measures the degree of acidity (0 – 14)
• Most biologic fluids are in the pH range
from 6 – 8
• Each pH unit represents a tenfold
difference (scale is logarithmic)
– A small change in pH actually indicates a
substantial change in H+ and OH-
concentrations.
20. Problem
How much greater is the [ H+ ] in a
solution with pH 2 than in a solution with
pH 6?
Answer:
pH of 2 = [ H+ ] of 1.0 x 10-2 = 1/100 M
pH of 6 = [ H+ ] of 1.0 x 10-6 = 1/1,000,000 M
10,000 times greater
21. Buffers
• A substance that eliminates large sudden
changes in pH.
• Buffers help organisms maintain the pH of
body fluids within the narrow range
necessary for life.
– Are combinations of H+ acceptors and
donors forms in a solution of weak acids
or bases
– Work by accepting H+ from solutions
when they are in excess and by donating
H+ when they have been depleted.
22. Acid Precipitation
• Rain, snow or fog with more strongly acidic than
pH of 5.6
• West Virginia has recorded 1.5
• East Tennessee reported 4.2 in 2000
• Occurs when sulfur oxides and nitrogen oxides
react with water in the atmosphere
– Lowers pH of soil which affects mineral
solubility – decline of forests
– Lower pH of lakes and ponds – In the
Western Adirondack Mountains, there are
lakes with a pH <5 that have no fish.